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Park I, Kim S, Brenden CK, Shi W, Iyer H, Bashir R, Vlasov Y. Highly Localized Chemical Sampling at Subsecond Temporal Resolution Enabled with a Silicon Nanodialysis Platform at Nanoliter per Minute Flows. ACS Nano 2024; 18:6963-6974. [PMID: 38378186 PMCID: PMC10919076 DOI: 10.1021/acsnano.3c09776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/22/2024]
Abstract
Microdialysis (MD) is a versatile and powerful technique for chemical profiling of biological tissues and is widely used for quantification of neurotransmitters, neuropeptides, metabolites, biomarkers, and drugs in the central nervous system as well as in dermatology, ophthalmology, and pain research. However, MD performance is severely limited by fundamental tradeoffs between chemical sensitivity, spatial resolution, and temporal response. Here, by using wafer-scale silicon microfabrication, we develop and demonstrate a nanodialysis (ND) sampling probe that enables highly localized chemical sampling with 100 μm spatial resolution and subsecond temporal resolution at high recovery rates. These performance metrics, which are 100-1000× superior to existing MD approaches, are enabled by a 100× reduction of the microfluidic channel cross-section, a corresponding drastic 100× reduction of flow rates to exceedingly slow few nL/min flows, and integration of a nanometer-thin nanoporous membrane with high transport flux into the probe sampling area. Miniaturized ND probes may allow for the minimally invasive and highly localized sampling and chemical profiling in live biological tissues with high spatiotemporal resolution for clinical, biomedical, and pharmaceutical applications.
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Affiliation(s)
| | | | | | - Weihua Shi
- University of Illinois at
Urbana−Champaign, Urbana, Illinois 61820, United States
| | - Hrishikesh Iyer
- University of Illinois at
Urbana−Champaign, Urbana, Illinois 61820, United States
| | - Rashid Bashir
- University of Illinois at
Urbana−Champaign, Urbana, Illinois 61820, United States
| | - Yurii Vlasov
- University of Illinois at
Urbana−Champaign, Urbana, Illinois 61820, United States
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Samiei T, Zou Z, Imani M, Nozari E. Optimal decoding of neural dynamics occurs at mesoscale spatial and temporal resolutions. Front Cell Neurosci 2024; 18:1287123. [PMID: 38419658 PMCID: PMC10899419 DOI: 10.3389/fncel.2024.1287123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 01/23/2024] [Indexed: 03/02/2024] Open
Abstract
Introduction Understanding the neural code has been one of the central aims of neuroscience research for decades. Spikes are commonly referred to as the units of information transfer, but multi-unit activity (MUA) recordings are routinely analyzed in aggregate forms such as binned spike counts, peri-stimulus time histograms, firing rates, or population codes. Various forms of averaging also occur in the brain, from the spatial averaging of spikes within dendritic trees to their temporal averaging through synaptic dynamics. However, how these forms of averaging are related to each other or to the spatial and temporal units of information representation within the neural code has remained poorly understood. Materials and methods In this work we developed NeuroPixelHD, a symbolic hyperdimensional model of MUA, and used it to decode the spatial location and identity of static images shown to n = 9 mice in the Allen Institute Visual Coding-NeuroPixels dataset from large-scale MUA recordings. We parametrically varied the spatial and temporal resolutions of the MUA data provided to the model, and compared its resulting decoding accuracy. Results For almost all subjects, we found 125ms temporal resolution to maximize decoding accuracy for both the spatial location of Gabor patches (81 classes for patches presented over a 9×9 grid) as well as the identity of natural images (118 classes corresponding to 118 images) across the whole brain. This optimal temporal resolution nevertheless varied greatly between different regions, followed a sensory-associate hierarchy, and was significantly modulated by the central frequency of theta-band oscillations across different regions. Spatially, the optimal resolution was at either of two mesoscale levels for almost all mice: the area level, where the spiking activity of all neurons within each brain area are combined, and the population level, where neuronal spikes within each area are combined across fast spiking (putatively inhibitory) and regular spiking (putatively excitatory) neurons, respectively. We also observed an expected interplay between optimal spatial and temporal resolutions, whereby increasing the amount of averaging across one dimension (space or time) decreases the amount of averaging that is optimal across the other dimension, and vice versa. Discussion Our findings corroborate existing empirical practices of spatiotemporal binning and averaging in MUA data analysis, and provide a rigorous computational framework for optimizing the level of such aggregations. Our findings can also synthesize these empirical practices with existing knowledge of the various sources of biological averaging in the brain into a new theory of neural information processing in which the unit of information varies dynamically based on neuronal signal and noise correlations across space and time.
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Affiliation(s)
- Toktam Samiei
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Zhuowen Zou
- Department of Computer Science, University of California, Irvine, Irvine, CA, United States
| | - Mohsen Imani
- Department of Computer Science, University of California, Irvine, Irvine, CA, United States
| | - Erfan Nozari
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
- Department of Electrical and Computer Engineering, University of California, Riverside, Riverside, CA, United States
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
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Fabrizio P, Alcolei A, Solari F. Considering Caenorhabditis elegans Aging on a Temporal and Tissue Scale: The Case of Insulin/IGF-1 Signaling. Cells 2024; 13:288. [PMID: 38334680 PMCID: PMC10854721 DOI: 10.3390/cells13030288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 01/24/2024] [Accepted: 01/31/2024] [Indexed: 02/10/2024] Open
Abstract
The aging process is inherently complex, involving multiple mechanisms that interact at different biological scales. The nematode Caenorhabditis elegans is a simple model organism that has played a pivotal role in aging research following the discovery of mutations extending lifespan. Longevity pathways identified in C. elegans were subsequently found to be conserved and regulate lifespan in multiple species. These pathways intersect with fundamental hallmarks of aging that include nutrient sensing, epigenetic alterations, proteostasis loss, and mitochondrial dysfunction. Here we summarize recent data obtained in C. elegans highlighting the importance of studying aging at both the tissue and temporal scale. We then focus on the neuromuscular system to illustrate the kinetics of changes that take place with age. We describe recently developed tools that enabled the dissection of the contribution of the insulin/IGF-1 receptor ortholog DAF-2 to the regulation of worm mobility in specific tissues and at different ages. We also discuss guidelines and potential pitfalls in the use of these new tools. We further highlight the opportunities that they present, especially when combined with recent transcriptomic data, to address and resolve the inherent complexity of aging. Understanding how different aging processes interact within and between tissues at different life stages could ultimately suggest potential intervention points for age-related diseases.
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Affiliation(s)
- Paola Fabrizio
- Laboratoire de Biologie et Modélisation de la Cellule, Ecole Normale Supérieure de Lyon, CNRS UMR5239, INSERM 1210, University Claude Bernard Lyon 1, 69364 Lyon, France;
| | - Allan Alcolei
- INMG, MeLiS, CNRS UMR 5284, INSERM U1314, University Claude Bernard Lyon 1, 69008 Lyon, France;
| | - Florence Solari
- INMG, MeLiS, CNRS UMR 5284, INSERM U1314, University Claude Bernard Lyon 1, 69008 Lyon, France;
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Papesh MA, Koerner T. Clinical Gaps-in-Noise Measures in Blast-Exposed Veterans: Associations with Electrophysiological and Behavioral Responses. Semin Hear 2024; 45:83-100. [PMID: 38370515 PMCID: PMC10872670 DOI: 10.1055/s-0043-1770139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024] Open
Abstract
It has been established that blast exposure and brain injury can result in self-reported and measured auditory processing deficits in individuals with normal or near-normal hearing sensitivity. However, the impaired sensory and/or cognitive mechanisms underlying these auditory difficulties are largely unknown. This work used a combination of behavioral and electrophysiological measures to explore how neural stimulus discrimination and processing speed contribute to impaired temporal processing in blast-exposed Veterans measured using the behavioral Gaps-in-Noise (GIN) Test. Results confirm previous findings that blast exposure can impact performance on the GIN and effect neural auditory discrimination, as measured using the P3 auditory event-related potential. Furthermore, analyses revealed correlations between GIN thresholds, P3 responses, and a measure of behavioral reaction time. Overall, this work illustrates that behavioral responses to the GIN are dependent on both auditory-specific bottom-up processing beginning with the neural activation of the cochlea and auditory brainstem as well as contributions from complex neural networks involved in processing speed and task-dependent target detection.
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Affiliation(s)
- Melissa A. Papesh
- VA National Center for Rehabilitative Auditory Research, Portland VA Medical Center, Portland, Oregon
- Department of Otolaryngology Head and Neck Surgery, Oregon Health and Science University, Portland, Oregon
| | - Tess Koerner
- VA National Center for Rehabilitative Auditory Research, Portland VA Medical Center, Portland, Oregon
- Department of Otolaryngology Head and Neck Surgery, Oregon Health and Science University, Portland, Oregon
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Jeong S, Koh D, Gwak E, Srambickal CV, Seo D, Widengren J, Lee JC. Pushing the Resolution Limit of Stimulated Emission Depletion Optical Nanoscopy. Int J Mol Sci 2023; 25:26. [PMID: 38203197 PMCID: PMC10779414 DOI: 10.3390/ijms25010026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024] Open
Abstract
Optical nanoscopy, also known as super-resolution optical microscopy, has provided scientists with the means to surpass the diffraction limit of light microscopy and attain new insights into nanoscopic structures and processes that were previously inaccessible. In recent decades, numerous studies have endeavored to enhance super-resolution microscopy in terms of its spatial (lateral) resolution, axial resolution, and temporal resolution. In this review, we discuss recent efforts to push the resolution limit of stimulated emission depletion (STED) optical nanoscopy across multiple dimensions, including lateral resolution, axial resolution, temporal resolution, and labeling precision. We introduce promising techniques and methodologies building on the STED concept that have emerged in the field, such as MINSTED, isotropic STED, and event-triggered STED, and evaluate their respective strengths and limitations. Moreover, we discuss trade-off relationships that exist in far-field optical microscopy and how they come about in STED optical nanoscopy. By examining the latest developments addressing these aspects, we aim to provide an updated overview of the current state of STED nanoscopy and its potential for future research.
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Affiliation(s)
- Sejoo Jeong
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Dongbin Koh
- School of Undergraduate Studies, DGIST, Daegu 42988, Republic of Korea
| | - Eunha Gwak
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Chinmaya V. Srambickal
- Exp. Biomol. Physics, Dept. Applied Physics, KTH—Royal Institute of Technology, 106 91 Stockholm, Sweden
| | - Daeha Seo
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| | - Jerker Widengren
- Exp. Biomol. Physics, Dept. Applied Physics, KTH—Royal Institute of Technology, 106 91 Stockholm, Sweden
| | - Jong-Chan Lee
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
- New Biology Research Center, DGIST, Daegu 42988, Republic of Korea
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Oyama K, Ichinohe F, Yamada A, Kitoh Y, Adachi Y, Hayashihara H, Nickel MD, Maruyama K, Fujinaga Y. Optimal Temporal Resolution to Achieve Good Image Quality and Perform Pharmacokinetic Analysis in Free-breathing Dynamic Contrast-enhanced MR Imaging of the Pancreas. Magn Reson Med Sci 2023; 22:477-485. [PMID: 36002311 PMCID: PMC10552666 DOI: 10.2463/mrms.mp.2022-0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/09/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The optimal temporal resolution for free-breathing dynamic contrast-enhanced MRI (FBDCE-MRI) of the pancreas has not been determined. This study aimed to evaluate the appropriate temporal resolution to achieve good image quality and to perform pharmacokinetic analysis in FBDCE-MRI of the pancreas using golden-angle radial sparse parallel (GRASP). METHODS Sixteen participants (53 ± 15 years, eight females) undergoing FBDCE-MRI were included in this prospective study. Images were retrospectively reconstructed at four temporal resolutions (1.8, 3.0, 4.8, and 7.8s). Two radiologists (5 years of experience) evaluated the image quality of each reconstructed image by assessing the visualization of the celiac artery (CEA), the common hepatic artery, the splenic artery, each area of the pancreas, and artifacts using a 5-point scale. Using Tissue-4D, pharmacokinetic parameters were calculated for each area in the reconstructed images at each temporal resolution for 16 examinations, excluding two with errors in the pharmacokinetic modeling analysis. Friedman and Bonferroni tests were used for analysis. A P value < 0.05 was considered statistically significant. RESULTS During vascular assessment, only scores for the CEA at 7.8s were significantly lower than the other temporal resolutions. Scores of all pancreatic regions and artifacts were significantly lower at 1.8s than at 4.8s and 7.8s. In the pharmacokinetic analysis, all volume transfer coefficients (Ktrans), rate constants (Kep), and the initial area under the concentration curve (iAUC) in the pancreatic head and tail were significantly lower at 4.8s and 7.8s than at 1.8s. iAUC in the pancreatic body and extracellular extravascular volume fraction (Ve) in the pancreatic head were significantly lower at 7.8s than at 1.8s. CONCLUSION A temporal resolution of 3.0s is appropriate to achieve image quality and perform pharmacokinetic analysis in FBDCE-MRI of the pancreas using GRASP.
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Affiliation(s)
- Kazuki Oyama
- Department of Radiology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Fumihito Ichinohe
- Department of Radiology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Akira Yamada
- Department of Radiology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Yoshihiro Kitoh
- Radiology Division, Shinshu University Hospital, Matsumoto, Nagano, Japan
| | - Yasuo Adachi
- Radiology Division, Shinshu University Hospital, Matsumoto, Nagano, Japan
| | - Hayato Hayashihara
- Radiology Division, Shinshu University Hospital, Matsumoto, Nagano, Japan
| | - Marcel D. Nickel
- MR Application Predevelopment, Siemens Healthcare GmbH, Allee am Roethelheimpark, Erlangen, Germany
| | - Katsuya Maruyama
- MR Research & Collaboration Department, Siemens Healthcare K.K., Tokyo, Japan
| | - Yasunari Fujinaga
- Department of Radiology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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Meyer RC, Weigelt-Fischer K, Tschiersch H, Topali G, Altschmied L, Heuermann MC, Knoch D, Kuhlmann M, Zhao Y, Altmann T. Dynamic growth QTL action in diverse light environments: characterization of light regime-specific and stable QTL in Arabidopsis. J Exp Bot 2023; 74:5341-5362. [PMID: 37306093 DOI: 10.1093/jxb/erad222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 06/10/2023] [Indexed: 06/13/2023]
Abstract
Plant growth is a complex process affected by a multitude of genetic and environmental factors and their interactions. To identify genetic factors influencing plant performance under different environmental conditions, vegetative growth was assessed in Arabidopsis thaliana cultivated under constant or fluctuating light intensities, using high-throughput phenotyping and genome-wide association studies. Daily automated non-invasive phenotyping of a collection of 382 Arabidopsis accessions provided growth data during developmental progression under different light regimes at high temporal resolution. Quantitative trait loci (QTL) for projected leaf area, relative growth rate, and PSII operating efficiency detected under the two light regimes were predominantly condition-specific and displayed distinct temporal activity patterns, with active phases ranging from 2 d to 9 d. Eighteen protein-coding genes and one miRNA gene were identified as potential candidate genes at 10 QTL regions consistently found under both light regimes. Expression patterns of three candidate genes affecting projected leaf area were analysed in time-series experiments in accessions with contrasting vegetative leaf growth. These observations highlight the importance of considering both environmental and temporal patterns of QTL/allele actions and emphasize the need for detailed time-resolved analyses under diverse well-defined environmental conditions to effectively unravel the complex and stage-specific contributions of genes affecting plant growth processes.
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Affiliation(s)
- Rhonda C Meyer
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Kathleen Weigelt-Fischer
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Henning Tschiersch
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Georgia Topali
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Lothar Altschmied
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Marc C Heuermann
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Dominic Knoch
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Markus Kuhlmann
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Yusheng Zhao
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Breeding Research, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
| | - Thomas Altmann
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, OT Gatersleben, Corrensstraße 3, D-06466 Seeland, Germany
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Kang H, Kim J, Kim J. Integrated High-Temporal-Resolution and High-Density Subretinal Prosthesis Using a Correlated Double-Sampling Technique. Sensors (Basel) 2023; 23:6501. [PMID: 37514794 PMCID: PMC10383336 DOI: 10.3390/s23146501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/05/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023]
Abstract
This paper presents a 1600-pixel integrated neural stimulator with a correlated double-sampling readout (DSR) circuit for a subretinal prosthesis. The retinal stimulation chip inserted beneath the photoreceptor layer comprises an array of an active pixel sensor (APS) and biphasic pulse shaper. The DSR circuit achieves a high signal-to-noise ratio (SNR) of the APS with a short integration time to simultaneously improve the temporal and spatial resolutions of restored vision. This DSR circuit is adopted along with a 5 × 5-pixel tile, which reduces pixel size and improves the SNR by increasing the area occupied by storage capacitors. Moreover, a low-mismatch reference generator enables a low standard deviation between individual pulse shapers. The 1600-pixel retinal chip, fabricated using the 0.18 μm 1P6M CMOS process, occupies a total area of 4.3 mm × 3.3 mm and dissipates an average power of 3.4 mW; this was demonstrated by determining the stimulus current patterns corresponding to the illuminations of an LCD projector. Experimental results show that the proposed high-density stimulation array chip can achieve a high temporal resolution owing to its short integration time.
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Affiliation(s)
- Hosung Kang
- Department of Medical Science, Korea University, Seoul 02841, Republic of Korea
| | - Jungyeon Kim
- Department of Health Sciences & Technology, Gachon Advanced Institute for Health Sciences & Technology, Gachon University, Incheon 21936, Republic of Korea
- Cellico Research and Development Laboratory, Sungnam-si 13449, Republic of Korea
| | - Jungsuk Kim
- Department of Biomedical Engineering, Gachon University, Incheon 21936, Republic of Korea
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Polishchuk LV, Kasparson AA. Temporal resolution of birth rate analysis in zooplankton and its implications for identifying strong interactions in ecology. Ecol Evol 2023; 13:e10341. [PMID: 37496758 PMCID: PMC10366112 DOI: 10.1002/ece3.10341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/03/2023] [Indexed: 07/28/2023] Open
Abstract
Expanding on Haeckel's classical definition, ecology can be defined as the study of strong and weak interactions between the organism and the environment, hence the need for identifying strong interactions as major drivers of population and community dynamics. The solution to this problem is facilitated by the fact that the frequency distribution of interaction strengths is highly skewed, resulting in few or, according to Liebig's law of the minimum, just one strong interaction. However, a single strong interaction often remains elusive. One of the reasons may be that, due to the ever-present dynamics of ecological systems, a single strong interaction is likely to exist only on relatively short time intervals, so methods with sufficient temporal resolution are required. In this paper, we study the temporal resolution of contribution analysis of birth rate in zooplankton, a method to assess the relative strength of bottom-up (food) versus top-down (predation) effects. Birth rate is estimated by the Edmondson-Paloheimo model. Our test system is a population of the cladoceran Bosmina longirostris inhabiting a small northern lake with few planktivorous predators, and thus likely controlled by food. We find that the method's temporal resolution in detecting bottom-up effects corresponds well to the species' generation time, and the latter seems comparable to the lifetime of a single strong interaction. This enables one to capture a single strong interaction "on the fly," right during its time of existence. We suggest that this feature, the temporal resolution of about the lifetime of a single strong interaction, may be a generally desirable property for any method, not only the one studied here, intended to identify and assess strong interactions. Success in disentangling strong interactions in ecological communities, and thus solving one of the key issues in ecology, may critically depend on the temporal resolution of the methods used.
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Affiliation(s)
- Leonard V. Polishchuk
- Department of General Ecology and Hydrobiology, Biological FacultyLomonosov Moscow State UniversityMoscowRussia
| | - Anna A. Kasparson
- Kharkevich Institute for Information Transmission ProblemsRussian Academy of SciencesMoscowRussia
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Leite Filho CA, Rocha-Muniz CN, Pereira LD, Schochat E. Auditory temporal resolution and backward masking in musicians with absolute pitch. Front Neurosci 2023; 17:1151776. [PMID: 37139520 PMCID: PMC10149789 DOI: 10.3389/fnins.2023.1151776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/27/2023] [Indexed: 05/05/2023] Open
Abstract
Among the many questions regarding the ability to effortlessly name musical notes without a reference, also known as absolute pitch, the neural processes by which this phenomenon operates are still a matter of debate. Although a perceptual subprocess is currently accepted by the literature, the participation of some aspects of auditory processing still needs to be determined. We conducted two experiments to investigate the relationship between absolute pitch and two aspects of auditory temporal processing, namely temporal resolution and backward masking. In the first experiment, musicians were organized into two groups according to the presence of absolute pitch, as determined by a pitch identification test, and compared regarding their performance in the Gaps-in-Noise test, a gap detection task for assessing temporal resolution. Despite the lack of statistically significant difference between the groups, the Gaps-in-Noise test measures were significant predictors of the measures for pitch naming precision, even after controlling for possible confounding variables. In the second experiment, another two groups of musicians with and without absolute pitch were submitted to the backward masking test, with no difference between the groups and no correlation between backward masking and absolute pitch measures. The results from both experiments suggest that only part of temporal processing is involved in absolute pitch, indicating that not all aspects of auditory perception are related to the perceptual subprocess. Possible explanations for these findings include the notable overlap of brain areas involved in both temporal resolution and absolute pitch, which is not present in the case of backward masking, and the relevance of temporal resolution to analyze the temporal fine structure of sound in pitch perception.
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Affiliation(s)
- Carlos Alberto Leite Filho
- Auditory Processing Lab, Department of Physical Therapy, Speech-Language Pathology and Occupational Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
- *Correspondence: Carlos Alberto Leite Filho,
| | - Caroline Nunes Rocha-Muniz
- Speech-Language Pathology Department, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil
| | - Liliane Desgualdo Pereira
- Neuroaudiology Lab, Department of Speech Therapy, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Eliane Schochat
- Auditory Processing Lab, Department of Physical Therapy, Speech-Language Pathology and Occupational Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
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Milidonis X, Nazir MS, Chiribiri A. Impact of Temporal Resolution and Methods for Correction on Cardiac Magnetic Resonance Perfusion Quantification. J Magn Reson Imaging 2022; 56:1707-1719. [PMID: 35338754 PMCID: PMC9790572 DOI: 10.1002/jmri.28180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Acquisition of magnetic resonance first-pass perfusion images is synchronized to the patient's heart rate (HR) and governs the temporal resolution. This is inherently linked to the process of myocardial blood flow (MBF) quantification and impacts MBF accuracy but to an unclear extent. PURPOSE To assess the impact of temporal resolution on quantitative perfusion and compare approaches for accounting for its variability. STUDY TYPE Prospective phantom and retrospective clinical study. POPULATION AND PHANTOM Simulations, a cardiac perfusion phantom, and 30 patients with (16, 53%) or without (14, 47%) coronary artery disease. FIELD STRENGTH/SEQUENCE 3.0 T/2D saturation recovery spoiled gradient echo sequence. ASSESSMENT Dynamic perfusion data were simulated for a range of reference MBF (1 mL/g/min-5 mL/g/min) and HR (30 bpm-150 bpm). Perfusion imaging was performed in patients and a phantom for different temporal resolutions. MBF and myocardial perfusion reserve (MPR) were quantified without correction for temporal resolution or following correction by either MBF scaling based on the sampling interval or data interpolation prior to quantification. Simulated data were quantified using Fermi deconvolution, truncated singular value decomposition, and one-compartment modeling, whereas phantom and clinical data were quantified using Fermi deconvolution alone. STATISTICAL TESTS Shapiro-Wilk tests for normality, percentage error (PE) for measuring MBF accuracy in simulations, and one-way repeated measures analysis of variance with Bonferroni correction to compare clinical MBF and MPR. Statistical significance set at P < 0.05. RESULTS For Fermi deconvolution and an example simulated 1 mL/g/min, the MBF PE without correction for temporal resolution was between 55.4% and -62.7% across 30-150 bpm. PE was between -22.2% and -6.8% following MBF scaling and between -14.2% and -14.2% following data interpolation across the same HR. An interpolated HR of 240 bpm reduced PE to ≤10%. Clinical rest and stress MBF and MPR were significantly different between analyses. DATA CONCLUSION Accurate perfusion quantification needs to account for the variability of temporal resolution, with data interpolation prior to quantification reducing MBF variability across different resolutions. LEVEL OF EVIDENCE 3 TECHNICAL EFFICACY STAGE: 1.
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Affiliation(s)
- Xenios Milidonis
- School of Biomedical Engineering & Imaging SciencesKing's College LondonLondonUK
| | | | - Amedeo Chiribiri
- School of Biomedical Engineering & Imaging SciencesKing's College LondonLondonUK
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12
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Nagler M, Podmirseg SM, Ascher‐Jenull J, Sint D, Traugott M. Why eDNA fractions need consideration in biomonitoring. Mol Ecol Resour 2022; 22:2458-2470. [PMID: 35652762 PMCID: PMC9545497 DOI: 10.1111/1755-0998.13658] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 05/12/2022] [Accepted: 05/26/2022] [Indexed: 11/29/2022]
Abstract
The analysis of environmental DNA (eDNA) is revolutionizing the monitoring of biodiversity as it allows to assess organismic diversity at large scale and unprecedented taxonomic detail. However, eDNA consists of an extracellular and intracellular fraction, each characterized by particular properties that determine the retrievable information on when and where organisms live or have been living. Here, we review the fractions of eDNA, describe how to obtain them from environmental samples and present a four-scenario concept that aims at enhancing spatial and temporal resolution of eDNA-based monitoring. Importantly, we highlight how the appropriate choice of eDNA fractions precludes misinterpretation of eDNA-based biodiversity data. Finally, future avenues of research towards eDNA fraction-specific analyses are outlined to unravel the full potential of eDNA-based studies targeting micro- and macro-organisms.
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Affiliation(s)
| | | | | | - Daniela Sint
- Department of ZoologyUniversität InnsbruckInnsbruckAustria
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13
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Mazaheri Y, Kim N, Lakhman Y, Jafari R, Vargas A, Otazo R. Dynamic contrast-enhanced MRI parametric mapping using high spatio temporal resolution Golden-angle RAdial Sparse Parallel MRI and iterative joint estimation of the arterial input function and pharmacokinetic parameters. NMR Biomed 2022; 35:e4718. [PMID: 35226774 PMCID: PMC9203940 DOI: 10.1002/nbm.4718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 02/17/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
The aim of this work is to develop a data-driven quantitative dynamic contrast-enhanced (DCE) MRI technique using Golden-angle RAdial Sparse Parallel (GRASP) MRI with high spatial resolution and high flexible temporal resolution and pharmacokinetic (PK) analysis with an arterial input function (AIF) estimated directly from the data obtained from each patient. DCE-MRI was performed on 13 patients with gynecological malignancy using a 3-T MRI scanner with a single continuous golden-angle stack-of-stars acquisition and image reconstruction with two temporal resolutions, by exploiting a unique feature in GRASP that reconstructs acquired data with user-defined temporal resolution. Joint estimation of the AIF (both AIF shape and delay) and PK parameters was performed with an iterative algorithm that alternates between AIF and PK estimation. Computer simulations were performed to determine the accuracy (expressed as percentage error [PE]) and precision of the estimated parameters. PK parameters (volume transfer constant [Ktrans ], fractional volume of the extravascular extracellular space [ve ], and blood plasma volume fraction [vp ]) and normalized root-mean-square error [nRMSE] (%) of the fitting errors for the tumor contrast kinetic data were measured both with population-averaged and data-driven AIFs. On patient data, the Wilcoxon signed-rank test was performed to compare nRMSE. Simulations demonstrated that GRASP image reconstruction with a temporal resolution of 1 s/frame for AIF estimation and 5 s/frame for PK analysis resulted in an absolute PE of less than 5% in the estimation of Ktrans and ve , and less than 11% in the estimation of vp . The nRMSE (mean ± SD) for the dual temporal resolution image reconstruction and data-driven AIF was 0.16 ± 0.04 compared with 0.27 ± 0.10 (p < 0.001) with 1 s/frame using population-averaged AIF, and 0.23 ± 0.07 with 5 s/frame using population-averaged AIF (p < 0.001). We conclude that DCE-MRI data acquired and reconstructed with the GRASP technique at dual temporal resolution can successfully be applied to jointly estimate the AIF and PK parameters from a single acquisition resulting in data-driven AIFs and voxelwise PK parametric maps.
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Affiliation(s)
- Yousef Mazaheri
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Nathanael Kim
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Yulia Lakhman
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Ramin Jafari
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Alberto Vargas
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Ricardo Otazo
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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14
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Tang FS, Yuan HL, Liu JB, Zhang G, Chen SY, Ke JB. Glutamate Transporters EAAT2 and EAAT5 Differentially Shape Synaptic Transmission from Rod Bipolar Cell Terminals. eNeuro 2022; 9:ENEURO.0074-22.2022. [PMID: 35523583 PMCID: PMC9121915 DOI: 10.1523/eneuro.0074-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/26/2022] [Accepted: 05/02/2022] [Indexed: 11/21/2022] Open
Abstract
Excitatory amino acid transporters (EAATs) control visual signal transmission in the retina by rapidly removing glutamate released from photoreceptors and bipolar cells (BCs). Although it has been reported that EAAT2 and EAAT5 are expressed at presynaptic terminals of photoreceptors and some BCs in mammals, the distinct functions of these two glutamate transporters in retinal synaptic transmission, especially at a single synapse, remain elusive. In this study, we found that EAAT2 was expressed in all BC types while coexisting with EAAT5 in rod bipolar (RB) cells and several types of cone BCs from mice of either sex. Our immunohistochemical study, together with a recently published literature (Gehlen et al., 2021), showed that EAAT2 and EAAT5 were both located in RB axon terminals near release sites. Optogenetic, electrophysiological and pharmacological analyses, however, demonstrated that EAAT2 and EAAT5 regulated neurotransmission at RB→AII amacrine cell synapses in significantly different ways: EAAT5 dramatically affected both the peak amplitude and kinetics of postsynaptic responses in AIIs, whereas EAAT2 had either relatively small or opposite effects. By contrast, blockade of EAAT1/GLAST, which was exclusively expressed in Müller cells, showed no obvious effect on AII responses, indicating that glutamate uptake by Müller cells did not influence synaptic transmission from RB terminals. Furthermore, we found that temporal resolution at RB→AII synapses was reduced substantially by blockade of EAAT5 but not EAAT2. Taken together, our work reveals the distinct functions of EAAT2 and EAAT5 in signal transmission at RB ribbon synapses.
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Affiliation(s)
| | | | | | | | | | - Jiang-Bin Ke
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
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15
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Ahmed Z, Rajendran K, Gong H, McCollough C, Leng S. Quantitative assessment of motion effects in dual-source dual-energy CT and dual-source photon-counting detector CT. Proc SPIE Int Soc Opt Eng 2022; 12031:120311P. [PMID: 35785242 PMCID: PMC9245006 DOI: 10.1117/12.2611030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Conventional dual-source CT scanners can be used to either provide better temporal resolution or dual-energy imaging, but not both at the same time. This presents a dilemma in cardiac CT as both high temporal resolution and multi-energy imaging are desirable. The current study evaluated a dual-source photon-counting-detector (DS-PCD) CT which can acquire multi-energy images at high temporal resolution. A cardiac motion phantom with a 3-mm diameter iodinated rod, mimicking the right coronary artery, was scanned 25 times using a DS-PCD CT (66 ms resolution) and a dual-source dual-energy (DS-DE, 125 ms resolution) CT. Low/high energy images and iodine maps were reconstructed at 40% and 75% cardiac phases. To quantify the impact of motion on image quality, dice similarity coefficient was computed between the low/high energy images while the circularity and effective diameter of the iodinated rod were computed on the iodine maps. The dice coefficients were higher for DS-PCD with a mean of 0.89 and 0.91 at the 40% and 70% phases, while DS-DE had a lower mean of 0.20 and 0.78, respectively. The circularity was excellent for DS-PCD with a mean of 0.97 and 0.98 at the 40% and 75% phases, while DS-DE had a mean of 0.71 and 0.98, respectively. The effective diameter was accurate for DS-PCD with a mean of 2.9 mm (true size of 3 mm) at both phases, while DS-DE had a mean of 4.0 mm and 3.2 mm at the 40% and 75% phases, respectively. These results indicate that DS-PCD CT enables simultaneous high temporal resolution and multi-energy cardiac imaging with minimal motion artifacts.
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Affiliation(s)
- Zaki Ahmed
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Hao Gong
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Shuai Leng
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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16
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Zhong Z, Sun K, Dan G, Luo Q, Zhou XJ. MRI with sub-millisecond temporal resolution over a reduced field of view. Magn Reson Med 2021; 86:3166-3174. [PMID: 34270138 PMCID: PMC8568630 DOI: 10.1002/mrm.28924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/26/2021] [Accepted: 06/22/2021] [Indexed: 11/06/2022]
Abstract
PURPOSE To demonstrate an MRI pulse sequence-Sub-millisecond Periodic Event Encoded Dynamic Imaging with a reduced field of view (or rFOV-SPEEDI)-for decreasing the scan times while achieving sub-millisecond temporal resolution. METHODS rFOV-SPEEDI was based on a variation of SPEEDI, known as get-SPEEDI, which used each echo in an echo-train to sample a distinct k-space raster by synchronizing with a cyclic event. This can produce a set of time-resolved images of the cyclic event with a temporal resolution determined by the echo spacing (typically < 1 ms). rFOV-SPEEDI incorporated a 2D radiofrequency (RF) pulse into get-SPEEDI to limit the field of view (FOV), leading to reduction in phase-encoding steps and subsequently decreased scan times without compromising the spatial resolution. Two experiments were performed at 3T to illustrate rFOV-SPEEDI's capability of capturing fast-changing electric currents in a phantom and the rapid opening and closing of aortic valve in human subjects over reduced FOVs. The results were compared with those from full FOV get-SPEEDI. RESULTS In the first experiment, the rapidly varying currents (50-200 Hz) were successfully captured with a temporal resolution of 0.8 ms, and agreed well with the applied currents. In the second experiment, the rapid opening and closing processes of aortic valve were clearly visualized with a temporal resolution of 0.6 ms over a reduced FOV (12 × 12 cm2 ). In both experiments, the acquisition times of rFOV-SPEEDI were decreased by 33%-50% relative to full FOV get-SPEEDI acquisitions and the spatial resolution was maintained. CONCLUSION Reducing the FOV is a viable approach to shortening the scan times in SPEEDI, which is expected to help stimulate SPEEDI applications for studying ultrafast, cyclic physiological and biophysical processes over a focal region.
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Affiliation(s)
- Zheng Zhong
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Kaibao Sun
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Guangyu Dan
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Qingfei Luo
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Xiaohong Joe Zhou
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
- Department of Radiology, University of Illinois at Chicago, Chicago, Illinois, USA
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
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Weise Valdés E, Barth P, Piran M, Laser KT, Burchert W, Körperich H. Left-Ventricular Reference Myocardial Strain Assessed by Cardiovascular Magnetic Resonance Feature Tracking and fSENC-Impact of Temporal Resolution and Cardiac Muscle Mass. Front Cardiovasc Med 2021; 8:764496. [PMID: 34796219 PMCID: PMC8593240 DOI: 10.3389/fcvm.2021.764496] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/11/2021] [Indexed: 11/16/2022] Open
Abstract
Aims: Cardiac strain parameters are increasingly measured to overcome shortcomings of ejection fraction. For broad clinical use, this study provides reference values for the two strain assessment methods feature tracking (FT) and fast strain-encoded (fSENC) cardiovascular magnetic resonance (CMR) imaging, including the child/adolescent group and systematically evaluates the influence of temporal resolution and muscle mass on strain. Methods and Results: Global longitudinal (GLS), circumferential (GCS), and radial (GRS) strain values in 181 participants (54% women, 11–70 years) without cardiac illness were assessed with FT (CVI42® software). GLS and GCS were also analyzed using fSENC (MyoStrain® software) in a subgroup of 84 participants (60% women). Fourteen patients suffering hypertrophic cardiomyopathy (HCM) were examined with both techniques. CMR examinations were done on a 3.0T MR-system. FT-GLS, FT-GCS, and FT-GRS were −16.9 ± 1.8%, −19.2 ± 2.1% and 34.2 ± 6.1%. fSENC-GLS was higher at −20.3 ± 1.8% (p < 0.001). fSENC-GCS was comparable at−19.7 ± 1.8% (p = 0.06). All values were lower in men (p < 0.001). Cardiac muscle mass correlated (p < 0.001) with FT-GLS (r = 0.433), FT-GCS (r = 0.483) as well as FT-GRS (r = −0.464) and acts as partial mediator for sex differences. FT-GCS, FT-GRS and fSENC-GLS correlated weakly with age. FT strain values were significantly lower at lower cine temporal resolutions, represented by heart rates (r = −0.301, −0.379, 0.385) and 28 or 45 cardiac phases per cardiac cycle (0.3–1.9% differences). All values were lower in HCM patients than in matched controls (p < 0.01). Cut-off values were −15.0% (FT-GLS), −19.3% (FT-GCS), 32.7% (FT-GRS), −17.2% (fSENC-GLS), and −17.7% (fSENC-GCS). Conclusion: The analysis of reference values highlights the influence of gender, temporal resolution, cardiac muscle mass and age on myocardial strain values.
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Affiliation(s)
- Elena Weise Valdés
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center North Rhine-Westphalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| | - Peter Barth
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center North Rhine-Westphalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| | - Misagh Piran
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center North Rhine-Westphalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| | - Kai Thorsten Laser
- Center for Congenital Heart Defects, Heart and Diabetes Center North Rhine-Westphalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| | - Wolfgang Burchert
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center North Rhine-Westphalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| | - Hermann Körperich
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center North Rhine-Westphalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
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Bebié P, Becker R, Commichau V, Debus J, Dissertori G, Djambazov L, Eleftheriou A, Fischer J, Fischer P, Ito M, Khateri P, Lustermann W, Ritzer C, Ritzert M, Röser U, Tsoumpas C, Warnock G, Weber B, Wyss MT, Zagozdzinska-Bochenek A. SAFIR-I: Design and Performance of a High-Rate Preclinical PET Insert for MRI. Sensors (Basel) 2021; 21:7037. [PMID: 34770344 PMCID: PMC8588038 DOI: 10.3390/s21217037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 11/16/2022]
Abstract
(1) Background: Small Animal Fast Insert for MRI detector I (SAFIR-I) is a preclinical Positron Emission Tomography (PET) insert for the Bruker BioSpec 70/30 Ultra Shield Refrigerated (USR) preclinical 7T Magnetic Resonance Imaging (MRI) system. It is designed explicitly for high-rate kinetic studies in mice and rats with injected activities reaching 500MBq, enabling truly simultaneous quantitative PET and Magnetic Resonance (MR) imaging with time frames of a few seconds in length. (2) Methods: SAFIR-I has an axial field of view of 54.2mm and an inner diameter of 114mm. It employs Lutetium Yttrium OxyorthoSilicate (LYSO) crystals and Multi Pixel Photon Counter (MPPC) arrays. The Position-Energy-Timing Application Specific Integrated Circuit, version 6, Single Ended (PETA6SE) digitizes the MPPC signals and provides time stamps and energy information. (3) Results: SAFIR-I is MR-compatible. The system's Coincidence Resolving Time (CRT) and energy resolution are between separate-uncertainty 209.0(3)ps and separate-uncertainty 12.41(02) Full Width at Half Maximum (FWHM) at low activity and separate-uncertainty 326.89(12)ps and separate-uncertainty 20.630(011) FWHM at 550MBq, respectively. The peak sensitivity is ∼1.6. The excellent performance facilitated the successful execution of first in vivo rat studies beyond 300MBq. Based on features visible in the acquired images, we estimate the spatial resolution to be ∼2mm in the center of the Field Of View (FOV). (4) Conclusion: The SAFIR-I PET insert provides excellent performance, permitting simultaneous in vivo small animal PET/MR image acquisitions with time frames of a few seconds in length at activities of up to 500MBq.
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Affiliation(s)
- Pascal Bebié
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Robert Becker
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Volker Commichau
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Jan Debus
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Günther Dissertori
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Lubomir Djambazov
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Afroditi Eleftheriou
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland; (A.E.); (G.W.); (B.W.); (M.T.W.)
| | - Jannis Fischer
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Peter Fischer
- Institute of Computer Engineering, Heidelberg University, 69120 Heidelberg, Germany; (P.F.); (M.R.)
| | - Mikiko Ito
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Parisa Khateri
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Werner Lustermann
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Christian Ritzer
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Michael Ritzert
- Institute of Computer Engineering, Heidelberg University, 69120 Heidelberg, Germany; (P.F.); (M.R.)
| | - Ulf Röser
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
| | - Charalampos Tsoumpas
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK;
| | - Geoffrey Warnock
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland; (A.E.); (G.W.); (B.W.); (M.T.W.)
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland; (A.E.); (G.W.); (B.W.); (M.T.W.)
| | - Matthias T. Wyss
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland; (A.E.); (G.W.); (B.W.); (M.T.W.)
| | - Agnieszka Zagozdzinska-Bochenek
- Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland; (R.B.); (V.C.); (J.D.); (G.D.); (L.D.); (J.F.); (M.I.); (P.K.); (W.L.); (C.R.); (U.R.); (A.Z.-B.)
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Tian M, Yang L. [Advances in on-line enzyme assays by sequence analysis-based capillary electrophoresis]. Se Pu 2020; 38:1143-53. [PMID: 34213111 DOI: 10.3724/SP.J.1123.2020.05008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Due to unique advantages such as short analysis time, high separation efficiency and sensitivity, easy automation, extremely low sample and reagent volume requirements, and the ability to utilize several detection methods, capillary electrophoresis (CE) is used as a high-efficiency separation technique, and has been developed as a powerful tool for on-line enzyme assays. On-line enzyme assays based on CE have been applied to almost all aspects of enzyme assays over the past two decades, including the evaluation of enzyme activities and kinetics, identification and characterization of enzyme inhibitors and activators, detection of enzyme substrates, investigation of enzyme-mediated metabolic pathways, and proteome analysis. One potential use of enzyme assays is in tracing enzymatic reactions from beginning to the end at high temporal resolution. Measurements of enzyme reactions at high temporal resolution can result in more accurate estimates of reaction mechanisms and reaction rate constants, which is vitally important for improving understanding of the functions of enzymes in metabolism and for identifying the potential use of enzymes in clinical diagnostics. Furthermore, high-throughput online enzyme analysis is of great importance for the analysis of enzyme reactions and enzyme inhibition reactions. The development of accurate, rapid and high-throughput enzyme inhibition screening methods is especially important for accelerating the development of new drugs. Electrophoretically mediated microanalysis (EMMA) and CE-integrated immobilized enzyme microreactor (IMER) are the two most used techniques for online CE enzyme assays. The EMMA technique utilizes different electrophoretic mobilities of enzymes and substrates to initiate reactions within the capillary and to separate the components of the reaction mixture for the final in-capillary quantification. In a CE-integrated IMER, the enzyme is bound to the capillary surface or to a suitable carrier attached to the capillary through physical adsorption, cross-linking, covalent bonding or other methods. The enzyme reactor is usually located at one end of the capillary; the enzyme-catalyzed reaction occurs when the substrates pass through the enzyme reactor and the substrates/products of the enzymatic reaction are separated and online detected by CE at the downstream end of the capillary. In both either techniques, the samples are usually introduced into the capillary by electrokinetic injection or by hydrodynamic injection. Because both injection methods require that the capillary inlet be physically moved from the sample container to the running buffer for CE analysis after each sample injection, it is unlikely that EMMA or microreactor techniques can be successfully used to perform sequential online analysis. Therefore, a CE sequence analysis technique based on rapid sequential injection has been developed as another powerful method for online enzyme analysis. Compared with the widely used electrokinetic and hydrodynamic injection methods used in traditional CE online enzyme analysis methods, rapid sequence injection methods can achieve sequential injection without any physical disturbance of the capillary inlet, allowing for the successful performance of online enzyme assays with high temporal resolution and at high throughput. A rapid, sequential, and automatic sample introduction system is an important part of online enzyme analysis based on CE sequence analysis. Several sequential injection methods such as optical-gating injection, flow-gated injection, two-dimension diffusion injection, flow injection and droplet microfluidics combined with CE have been developed to successfully perform online enzyme assays with high temporal resolution and high throughput. In this paper, we will review recently developed CE online enzyme assays and inhibition studies based on rapid sequential injection. We review the progress and applications of various sequential sample injection approaches that have been developed for sequential on-line CE analysis of enzyme reactions at high temporal resolution and high-throughput screening of enzyme inhibitors, including optical-gating injection, flow gated injection, two-dimension diffusion injection, flow injection and droplet microfluidics.
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Zhang Y, Cheng H, Huang D, Fu C. High Temporal Resolution Land Use Regression Models with POI Characteristics of the PM 2.5 Distribution in Beijing, China. Int J Environ Res Public Health 2021; 18:6143. [PMID: 34200158 PMCID: PMC8201188 DOI: 10.3390/ijerph18116143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/03/2022]
Abstract
PM2.5 is one of the primary components of air pollutants, and it has wide impacts on human health. Land use regression models have the typical disadvantage of low temporal resolution. In this study, various point of interests (POIs) variables are added to the usual predictive variables of the general land use regression (LUR) model to improve the temporal resolution. Hourly PM2.5 concentration data from 35 monitoring stations in Beijing, China, were used. Twelve LUR models were developed for working days and non-working days of the heating season and non-heating season, respectively. The results showed that these models achieved good fitness in winter and summer, and the highest R2 of the winter and summer models were 0.951 and 0.628, respectively. Meteorological factors, POIs, and roads factors were the most critical predictive variables in the models. This study also showed that POIs had time characteristics, and different types of POIs showed different explanations ranging from 5.5% to 41.2% of the models on working days or non-working days, respectively. Therefore, this study confirmed that POIs can greatly improve the temporal resolution of LUR models, which is significant for high precision exposure studies.
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Affiliation(s)
| | - Hongguang Cheng
- School of Environment, Beijing Normal University, Beijing 100875, China; (Y.Z.); (D.H.); (C.F.)
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21
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Abstract
While many studies have examined the auditory abilities of musicians, this study uniquely asks whether dance training, a similar yet understudied type of early-life training, also benefits auditory abilities. We focused this investigation on temporal resolution, given the importance of subtle temporal cues in synchronizing movement. We found that, compared to untrained controls, novice adult dancers who have trained continuously since childhood had enhanced temporal resolution, measured with a gap detection task. In an analysis involving current and former dancers, total years of training was a significant predictor of temporal resolution thresholds. The association between dance experience and improved auditory skills has implications for current theories of experience-dependent auditory plasticity and the design of sound-based educational and rehabilitation activities.
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Affiliation(s)
- Erika Skoe
- Department of Speech, Language, and Hearing Sciences, University of Connecticut, Storrs, Connecticut, United States
| | - Erica V Scarpati
- Department of Speech, Language, and Hearing Sciences, University of Connecticut, Storrs, Connecticut, United States
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22
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Chakrabarty M, Atsumi T, Kaneko A, Fukatsu R, Ide M. State anxiety modulates the effect of emotion cues on visual temporal sensitivity in autism spectrum disorder. Eur J Neurosci 2021; 54:4682-4694. [PMID: 33998735 DOI: 10.1111/ejn.15311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 05/10/2021] [Indexed: 12/28/2022]
Abstract
Atypical processing of stimulus inputs across a range of sensory modalities in autism spectrum disorder (ASD) is widely reported. Sensory processing is known to be influenced by bodily internal states such as physiological arousal and anxiety. As a sizeable proportion of ASD reportedly have co-morbid anxiety disorders that are linked with dysregulated arousal, we investigated if face emotion arousal cues influenced visual sensory sensitivity (indexed by temporal resolution) in ASD (n = 20) compared to a matched group of typically developed individuals (TD, n = 21). We asked further if emotion-cued changes in visual sensitivity were associated with individual differences in state and trait anxiety. Participants reported the laterality of the second of two consecutive Gaussian-blob flashes in a visual temporal order judgment task (v-TOJ), demanding higher-level visual processing. The key manipulation was presenting a task-irrelevant face emotion cue briefly at unexpected time points preceding the task-relevant flashes. Disgust vs. Neutral emotion signals significantly enhanced the visual temporal resolution in ASD. Individual state-anxiety scores showed a fair correlative trend with the emotion-cued changes in temporal resolution (Disgust versus Neutral) in ASD but missed statistical significance. Both these effects were absent in TD. The results show that individual state-anxiety levels likely modulate the effect of emotions on visual temporal sensitivity in ASD. The findings support a nuanced approach to understand the disparate sensory features in ASD, by factoring in the interplay of the individual reactivity to environmental affective information and the severity of anxiety.
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Affiliation(s)
- Mrinmoy Chakrabarty
- Department of Social Sciences and Humanities, Indraprastha Institute of Information Technology Delhi, New Delhi, India
| | - Takeshi Atsumi
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Department of Medical Physiology School of Medicine, Kyorin University, Tokyo, Japan
| | - Ayako Kaneko
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Reiko Fukatsu
- Department of Medical Physiology School of Medicine, Kyorin University, Tokyo, Japan
| | - Masakazu Ide
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
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23
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Zhong Z, Sun K, Dan G, Luo Q, Farzaneh-Far A, Karaman MM, Zhou XJ. Visualization of Human Aortic Valve Dynamics Using Magnetic Resonance Imaging with Sub-Millisecond Temporal Resolution. J Magn Reson Imaging 2021; 54:1246-1254. [PMID: 33761166 DOI: 10.1002/jmri.27603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Visualization of aortic valve dynamics is important in diagnosing valvular diseases but is challenging to perform with magnetic resonance imaging (MRI) due to the limited temporal resolution. PURPOSE To develop an MRI technique with sub-millisecond temporal resolution and demonstrate its application in visualizing rapid aortic valve opening and closing in human subjects in comparison with echocardiography and conventional MRI techniques. STUDY TYPE Prospective. POPULATION Twelve healthy subjects. FIELD STRENGTH/SEQUENCE 3 T; gradient-echo-train-based sub-millisecond periodic event encoded imaging (get-SPEEDI) and balanced steady-state free precession (bSSFP). ASSESSMENT Images were acquired using get-SPEEDI with a temporal resolution of 0.6 msec. get-SPEEDI was triggered by an electrocardiogram so that each echo in the gradient echo train corresponded to an image at a specific time point, providing a time-resolved characterization of aortic valve dynamics. For comparison, bSSFP was also employed with 12 msec and 24 msec temporal resolutions, respectively. The durations of the aortic valve rapid opening (Tro ), rapid closing (Trc ), and the maximal aortic valve area (AVA) normalized to height were measured with all three temporal resolutions. M-mode echocardiograms with a temporal resolution of 0.8 msec were obtained for further comparison. STATISTICAL TEST Parameters were compared between the three sequences, together with the echocardiography results, with a Mann-Whitney U test. RESULTS Significantly shorter Tro (mean ± SD: 27.5 ± 6.7 msec) and Trc (43.8 ± 11.6 msec) and larger maximal AVA/height (2.01 ± 0.29 cm2 /m) were measured with get-SPEEDI compared to either bSSFP sequence (Tro of 56.3 ± 18.8 and 63.8 ± 20.2 msec; Trc of 68.2 ± 16.6 and 72.8 ± 18.2 msec; maximal AVA/height of 1.63 ± 0.28 and 1.65 ± 0.32 cm2 /m for 12 msec and 24 msec temporal resolutions, respectively, P < 0.05). In addition, the get-SPEEDI results were more consistent with those measured using echocardiography, especially for Tro (29.0 ± 4.1 msec, P = 0.79) and Trc (41.6 ± 4.3 msec, P = 0.16). DATA CONCLUSION: get-SPEEDI allows for visualization of human aortic valve dynamics and provided values closer to those measured using echocardiography than the bSSFP sequences. LEVEL OF EVIDENCE 1 TECHNICAL EFFICACY STAGE: 1.
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Affiliation(s)
- Zheng Zhong
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Kaibao Sun
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Guangyu Dan
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Qingfei Luo
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Afshin Farzaneh-Far
- Department of Radiology, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Meryem Muge Karaman
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Xiaohong Joe Zhou
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Radiology, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
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24
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Wu Z, Xu X, Xi P. Stimulated emission depletion microscopy for biological imaging in four dimensions: A review. Microsc Res Tech 2021; 84:1947-1958. [PMID: 33713513 DOI: 10.1002/jemt.23750] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 02/27/2021] [Indexed: 12/26/2022]
Abstract
Stimulated emission depletion (STED) microscopy allows high lateral and axial resolution, long term imaging in living cells. Here we review recent technical advances in STED microscopy, with emphasis on resolution and measurement range of XYZt four dimensions. Different STED technical advances and novel STED probes are discussed with their respective application in biological subcellular imaging. This review may serve as a practical guide for choosing a suitable approach to the advanced STED super-resolution imaging.
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Affiliation(s)
- Zhaoyang Wu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Xinzhu Xu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Peng Xi
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China.,UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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25
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Meyer RC, Weigelt-Fischer K, Knoch D, Heuermann M, Zhao Y, Altmann T. Temporal dynamics of QTL effects on vegetative growth in Arabidopsis thaliana. J Exp Bot 2021; 72:476-490. [PMID: 33080013 DOI: 10.1093/jxb/eraa490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/19/2020] [Indexed: 06/11/2023]
Abstract
We assessed early vegetative growth in a population of 382 accessions of Arabidopsis thaliana using automated non-invasive high-throughput phenotyping. All accessions were imaged daily from 7 d to 18 d after sowing in three independent experiments and genotyped using the Affymetrix 250k SNP array. Projected leaf area (PLA) was derived from image analysis and used to calculate relative growth rates (RGRs). In addition, initial seed size was determined. The generated datasets were used jointly for a genome-wide association study that identified 238 marker-trait associations (MTAs) individually explaining up to 8% of the total phenotypic variation. Co-localization of MTAs occurred at 33 genomic positions. At 21 of these positions, sequential co-localization of MTAs for 2-9 consecutive days was observed. The detected MTAs for PLA and RGR could be grouped according to their temporal expression patterns, emphasizing that temporal variation of MTA action can be observed even during the vegetative growth phase, a period of continuous formation and enlargement of seemingly similar rosette leaves. This indicates that causal genes may be differentially expressed in successive periods. Analyses of the temporal dynamics of biological processes are needed to gain important insight into the molecular mechanisms of growth-controlling processes in plants.
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Affiliation(s)
- Rhonda C Meyer
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, Research Group Heterosis, OT Gatersleben, Corrensstraße, Seeland, Germany
| | - Kathleen Weigelt-Fischer
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, Research Group Heterosis, OT Gatersleben, Corrensstraße, Seeland, Germany
| | - Dominic Knoch
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, Research Group Heterosis, OT Gatersleben, Corrensstraße, Seeland, Germany
| | - Marc Heuermann
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, Research Group Heterosis, OT Gatersleben, Corrensstraße, Seeland, Germany
| | - Yusheng Zhao
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Breeding Research, Research Group Quantitative Genetics, OT Gatersleben, Corrensstraße, Seeland, Germany
| | - Thomas Altmann
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Molecular Genetics, Research Group Heterosis, OT Gatersleben, Corrensstraße, Seeland, Germany
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26
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Abstract
Cochlear implants electrically stimulate surviving auditory neurons in the cochlea to provide severely or profoundly deaf people with access to hearing. Signal processing strategies derive frequency-specific information from the acoustic signal and code amplitude changes in frequency bands onto amplitude changes of current pulses emitted by the tonotopically arranged intracochlear electrodes. This article first describes how parameters of the electrical stimulation influence the loudness evoked and then summarizes two different phenomenological models developed by McKay and colleagues that have been used to explain psychophysical effects of stimulus parameters on loudness, detection, and modulation detection. The Temporal Model is applied to single-electrode stimuli and integrates cochlear neural excitation using a central temporal integration window analogous to that used in models of normal hearing. Perceptual decisions are made using decision criteria applied to the output of the integrator. By fitting the model parameters to a variety of psychophysical data, inferences can be made about how electrical stimulus parameters influence neural excitation in the cochlea. The Detailed Model is applied to multi-electrode stimuli, and includes effects of electrode interaction at a cochlear level and a transform between integrated excitation and specific loudness. The Practical Method of loudness estimation is a simplification of the Detailed Model and can be used to estimate the relative loudness of any multi-electrode pulsatile stimuli without the need to model excitation at the cochlear level. Clinical applications of these models to novel sound processing strategies are described.
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Affiliation(s)
- Colette M. McKay
- Bionics Institute, Melbourne, VIC, Australia
- Department of Medical Bionics, University of Melbourne, Melbourne, VIC, Australia
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27
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Mashita R, Yashiro W, Kaneko D, Bito Y, Kishimoto H. High-speed rotating device for X-ray tomography with 10 ms temporal resolution. J Synchrotron Radiat 2021; 28:322-326. [PMID: 33399584 DOI: 10.1107/s1600577520014666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 11/05/2020] [Indexed: 06/12/2023]
Abstract
The temporal resolution of X-ray tomography, using a synchrotron radiation X-ray source, has been improved to millisecond order in recent years. However, the sample must be rotated at a speed of more than a few thousand revolutions per minute, which makes it difficult to control the environment around the sample. In this study, a high-speed rotation device has been developed, comprising two synchronized coaxial motors movable along the direction of the axis, which can stretch or compress the rotating sample. Using this device, tomograms of breaking rubber were successfully obtained at a temporal resolution of 10 ms.
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Affiliation(s)
- Ryo Mashita
- Sumitomo Rubber Industries Ltd, Kobe, Hyogo 651-0071, Japan
| | - Wataru Yashiro
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Japan
| | | | - Yasumasa Bito
- Sumitomo Rubber Industries Ltd, Kobe, Hyogo 651-0071, Japan
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28
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Lerer A, Bowman DD, Luh WM, Ohmes CM, Scrivani PV. Selected advanced imaging techniques were unable to quantify in vivo parasitic burden in heartworm-infested dogs. Vet Radiol Ultrasound 2020; 62:471-475. [PMID: 33350539 DOI: 10.1111/vru.12945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 11/26/2022] Open
Abstract
This prospective exploratory study aimed to determine whether certain noninvasive advanced imaging techniques could estimate parasitic burden in heartworm-infested dogs; a noninvasive method is needed for ethical considerations and permitting longitudinal drug studies. Three cardiac-gated and respiratory-gated 3T MRI techniques and CT pulmonary angiography (CTPA) were performed in three healthy beagles to optimize imaging techniques. Once the imaging techniques were established, a pilot study was performed to determine which one of the MRI techniques would be used in an observer comparison study. Ultimately, spoiled gradient recalled (SPGR)-cine-MRI and CTPA were performed in four and five heartworm-infested dogs, respectively. Heartworms were detected in the pulmonary arteries in all dogs during SPGR-cine-MRI and in no dog during CTPA. However, counting the number of worms was unsuccessful. In conclusion, CTPA and SPGR-cine-MRI were unable to replace necropsy for quantifying parasitic burden in heartworm-infested dogs.
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Affiliation(s)
- Assaf Lerer
- College of Veterinary Medicine, Department of Clinical Sciences, Cornell University, Ithaca, New York
| | - Dwight D Bowman
- College of Veterinary Medicine, Department of Microbiology and Immunology, Cornell University, Ithaca, New York
| | - Wen-Ming Luh
- Cornell MRI Facility, Cornell University, Ithaca, New York
| | | | - Peter V Scrivani
- College of Veterinary Medicine, Department of Clinical Sciences, Cornell University, Ithaca, New York
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29
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Zhong Z, Sun K, Karaman MM, Zhou XJ. Magnetic resonance imaging with submillisecond temporal resolution. Magn Reson Med 2020; 85:2434-2444. [PMID: 33252784 DOI: 10.1002/mrm.28588] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 09/20/2020] [Accepted: 10/17/2020] [Indexed: 11/10/2022]
Abstract
PURPOSE To demonstrate an MRI technique-Submillisecond Periodic Event Encoded Dynamic Imaging (SPEEDI)-for capturing cyclic dynamic events with submillisecond temporal resolution. METHODS The SPEEDI technique is based on an FID or an echo signal in which each time point in the signal is used to sample a distinct k-space raster, followed by repeated FIDs or echoes to produce the remaining k-space data in each k-space raster. All acquisitions are synchronized with a cyclic event, resulting in a set of time-resolved images of the cyclic event with a temporal resolution determined by the dwell time. In SPEEDI, spatial encoding is accomplished by phase encoding. The SPEEDI technique was demonstrated in two experiments at 3 T to (1) visualize fast-changing electric currents that mimicked the waveform of an action potential, and (2) characterize rapidly decaying eddy currents in an MRI system, with a temporal resolution of 0.2 ms and 0.4 ms, respectively. In both experiments, compressed sensing was incorporated to reduce the scan times. Phase difference maps related to the dynamics of electric currents or eddy currents were then obtained. RESULTS In the first experiment, time-resolved phase maps resulting from the action potential-mimicking current waveform were successfully obtained and agreed well with theoretical calculations (normalized RMS error = 0.07). In the second experiment, spatially resolved eddy current phase maps revealed time constants (27.1 ± 0.2 ms, 41.1 ± 3.5 ms, and 34.8 ± 0.7 ms) that matched well with those obtained from an established method using point sources (26.4 ms, 41.2 ms and 34.8 ms). For both experiments, phase maps from fully sampled and compressed-sensing-accelerated k-space data exhibited a high structural similarity (> 0.8) despite a two-fold to three-fold acceleration. CONCLUSIONS We have illustrated that SPEEDI can provide submillisecond temporal resolution. This capability will likely lead to future exploration of ultrafast, cyclic biomedical processes using MRI.
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Affiliation(s)
- Zheng Zhong
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Kaibao Sun
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
| | - M Muge Karaman
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Xiaohong Joe Zhou
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Radiology, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
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30
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Mishra SK, Saxena U. Basic Measures of Auditory Perception in Children: No Evidence for Mediation by Auditory Working Memory Capacity. Front Hum Neurosci 2020; 14:591101. [PMID: 33281586 PMCID: PMC7689342 DOI: 10.3389/fnhum.2020.591101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/19/2020] [Indexed: 11/13/2022] Open
Abstract
Immature auditory perception in children has generally been ascribed to deficiencies in cognitive factors, such as working memory and inattention. This notion appears to be commonly accepted for all children despite limited empirical evidence. In the present work, we examined whether working memory capacity would predict basic aspects of hearing, pure-tone frequency discrimination and temporal gap detection, in typically-developing, normal-hearing children (7–12 years). Contrary to our expectation, working memory capacity, as measured by digit spans, or intrinsic auditory attention (on- and off-task response variability) did not consistently predict the individual variability in auditory perception. Present results provide no evidence for a role of working memory capacity in basic measures of auditory perception in children. This lack of a relationship may partly explain why some children with perceptual deficits despite normal audiograms (commonly referred to as auditory processing disorders) may have typical cognitive abilities.
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Affiliation(s)
- Srikanta K Mishra
- Department of Communication Sciences & Disorders, The University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Udit Saxena
- MAA Institute of Speech & Hearing, Hyderabad, India
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31
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Matsushita T, Kurozumi A, Fujii S, Nishida N, Honda M. [Retrospective Study of Image Quality in Pediatric Cardiac Cine MRI]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2020; 76:699-704. [PMID: 32684562 DOI: 10.6009/jjrt.2020_jjrt_76.7.699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In pediatric cardiac cine magnetic resonance imaging (MRI), it must overcome several challenges including the patient's size and higher heart rate. The aim of this study was to retrospectively evaluate imaging optimization. Cardiac cine MRI data from 24 patients was analyzed (age range: 3 months-10 years, average age: 5 years, male/female: 11/13, R-R interval: 450±4 to 819±7 ms). About 11 cases out of 24 have good image quality. For small variations in the R-R interval and higher temporal resolution improved image quality with significant difference (P<0.05, Mann-Whitney U-test). In this study, values of temporal resolution <30 ms yielded good image quality for heart rates over 100 bpm. On the other hands, the factors dependent on the patient like heart rate and ejection fraction have no significant difference. The segmentation of data acquisition is more significant than recording small fields of view or thin slices for infantile and pediatric cardiac cine MRI. Similar to adult cases, variations in heart rate affect the image quality; however, we demonstrated that using segmentation of data acquisition results in improved image quality.
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Affiliation(s)
- Toshi Matsushita
- Department of Radiology, Division of Medical Technology, Okayama University Hospital
| | - Akira Kurozumi
- Department of Radiology, Division of Medical Technology, Okayama University Hospital
| | - Shunsuke Fujii
- Department of Radiology, Division of Medical Technology, Okayama University Hospital
| | - Naoki Nishida
- Department of Radiology, Division of Medical Technology, Okayama University Hospital
| | - Mitsugi Honda
- Department of Radiology, Division of Medical Technology, Okayama University Hospital
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32
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Li J, Guo B, Cui L, Huang H, Meng M. Dissociated modulations of multivoxel activation patterns in the ventral and dorsal visual pathways by the temporal dynamics of stimuli. Brain Behav 2020; 10:e01673. [PMID: 32496013 PMCID: PMC7375111 DOI: 10.1002/brb3.1673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 04/12/2020] [Accepted: 04/30/2020] [Indexed: 01/29/2023] Open
Abstract
INTRODUCTION Previous studies suggested temporal limitations of visual object identification in the ventral pathway. Moreover, multivoxel pattern analyses (MVPA) of fMRI activation have shown reliable encoding of various object categories including faces and tools in the ventral pathway. By contrast, the dorsal pathway is involved in reaching a target and grasping a tool, and quicker in processing the temporal dynamics of stimulus change. However, little is known about how activation patterns in both pathways may change according to the temporal dynamics of stimulus change. METHODS Here, we measured fMRI responses of two consecutive stimuli with varying interstimulus intervals (ISIs), and we compared how the two visual pathways respond to the dynamics of stimuli by using MVPA and information-based searchlight mapping. RESULTS We found that the temporal dynamics of stimuli modulate responses of the two visual pathways in opposite directions. Specifically, slower temporal dynamics (longer ISIs) led to greater activity and better MVPA results in the ventral pathway. However, faster temporal dynamics (shorter ISIs) led to greater activity and better MVPA results in the dorsal pathway. CONCLUSIONS These results are the first to show how temporal dynamics of stimulus change modulated multivoxel fMRI activation pattern change. And such temporal dynamic response function in different ROIs along the two visual pathways may shed lights on understanding functional relationship and organization of these ROIs.
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Affiliation(s)
- Jiaxin Li
- School of PsychologySouth China Normal UniversityGuangzhouChina
| | - Bingbing Guo
- School of PsychologySouth China Normal UniversityGuangzhouChina
| | - Lin Cui
- School of PsychologySouth China Normal UniversityGuangzhouChina
| | - Hong Huang
- School of PsychologySouth China Normal UniversityGuangzhouChina
| | - Ming Meng
- School of PsychologySouth China Normal UniversityGuangzhouChina
- Key Laboratory of BrainCognition and Education Sciences (South China Normal University)Ministry of EducationGuangzhouChina
- Center for Studies of Psychological ApplicationSouth China Normal UniversityGuangzhouChina
- Guangdong Key Laboratory of Mental Health and Cognitive ScienceSouth China Normal UniversityGuangzhouChina
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33
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Abstract
We investigated the temporal resolution of ionic current in solid-state nanopore sensors. Resistive pulses observed upon translocation of single-nanoparticles were found to become blunter as we imposed larger external resistance in series to the pore via the integrated microfluidic channels on the membrane. This was found to occur even when the out-of-pore resistance is more than an order of magnitude smaller than that at the nanopore, which can be understood as a predominant contribution of charging/discharging at the water-touching thin dielectrics to retard the response of the ionic current against ion blockage by a fast-moving object through the sensing zone. Most importantly, our results predict a time resolution of better than 12 ns, irrespective of the nanopore size, by optimizing the membrane capacitance and the external resistance that promises high-speed single-molecule sequencing by the ionic current at 106 base/s.
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Affiliation(s)
- Shohei Kishimoto
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Sanae Murayama
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Makusu Tsutsui
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Masateru Taniguchi
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
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34
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Abstract
Animals use their sensory systems to sample information from their environments. The physiological properties of sensory systems differ, leading animals to perceive their environments in different ways. For example, eyes have different temporal sampling rates, with faster-sampling eyes able to resolve faster-moving scenes. Eyes can also have different dynamic ranges. For every eye, there is a light level below which vision is unreliable because of an insufficient signal-to-noise ratio and a light level above which the photoreceptors are saturated. Here, we report that the eyes of the snapping shrimp Alpheus heterochaelis have a temporal sampling rate of at least 160 Hz, making them the fastest-sampling eyes ever described in an aquatic animal. Fast-sampling eyes help flying animals detect objects moving across their retinas at high angular velocities. A. heterochaelis are fast-moving animals that live in turbid, structurally complex oyster reefs and their fast-sampling eyes, like those of flying animals, may help them detect objects moving rapidly across their retinas. We also report that the eyes of A. heterochaelis have a broad dynamic range that spans conditions from late twilight (approx. 1 lux) to direct sunlight (approx. 100 000 lux), a finding consistent with the circatidal activity patterns of this shallow-dwelling species.
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Affiliation(s)
- Alexandra C N Kingston
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Daniel R Chappell
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Daniel I Speiser
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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Li Y, Garrett JW, Li K, Strother C, Chen GH. An Enhanced SMART-RECON Algorithm for Time-Resolved C-Arm Cone-Beam CT Imaging. IEEE Trans Med Imaging 2020; 39:1894-1905. [PMID: 31870980 PMCID: PMC7307269 DOI: 10.1109/tmi.2019.2960720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Temporal resolution in time-resolved cone-beam CT (TR-CBCT) imaging is often limited by the time needed to acquire a complete data set for image reconstruction. With the recent developments of performing nearly limited-view artifact-free reconstruction from data in a limited-view angle range and a prior image, temporal resolution of TR-CBCT imaging can be improved. One such an example is the use of Simultaneous Multiple Artifacts Reduction in Tomographic RECONstruction (SMART-RECON) [1] technique. However, with SMART-RECON, one can only improve temporal resolution up to 1 frame per second (fps) which is an improvement of 4.5 times over that of the conventional FBP reconstruction. In this paper, a new technique referred to as enhanced SMART-RECON (eSMART-RECON) was introduced to enhance the temporal performance of SMART-RECON in a multi-sweep CBCT data acquisition protocol. Both numerical simulation studies with ground truth and in vivo human subject studies using C-arm CBCT acquisition systems were conducted to demonstrate the following key results: for a multi-sweep CBCT acquisition protocol, eSMART-RECON enables 4-7.5 fps temporal resolution for TR-CBCT which is 4-7.5 times better than that offered by the original SMART-RECON, and 18-34 times better than that offered by the conventional FBP reconstruction.
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Ide M, Atsumi T, Chakrabarty M, Yaguchi A, Umesawa Y, Fukatsu R, Wada M. Neural Basis of Extremely High Temporal Sensitivity: Insights From a Patient With Autism. Front Neurosci 2020; 14:340. [PMID: 32425746 PMCID: PMC7203484 DOI: 10.3389/fnins.2020.00340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/23/2020] [Indexed: 01/24/2023] Open
Abstract
The human brain is sensitive to incoming sensory information across multiple time scales. Temporal scales of information represented in the brain generally constrain behavior. Despite reports of the neural correlates of millisecond timing, how the human brain processes sensory stimuli in the sub-second range (≤100 ms) and its behavioral implications are areas of active scientific inquiry. An autism spectrum disorder (ASD) patient showed a tactile discrimination threshold of 6.49 ms on a temporal order judgment (TOJ) task which was approximately 10-fold superior than other ASD and healthy controls (59 and 69 ms, respectively). To investigate the brain regions of this extremely high temporal resolution in the patient, we used functional magnetic resonance imaging (fMRI) during TOJ. We observed greater activity notably in the left superior temporal gyrus (STG) and precentral gyrus (PrG) compared to that of controls. Generally, the left superior frontal gyrus (SFG) correlated positively, while the opercular part of right inferior frontal gyrus (IFG) correlated negatively, with the correct TOJ rate across all subjects (the patient + 22 healthy controls). We found that the performance was negatively correlated with the strength of neural responses in the right IFG overall in 30 participants (the patient + 22 healthy and 7 ASD controls). Our data reveal superior ability of this particular case of ASD in the millisecond scale for sensory inputs. We highlight several neural correlates of TOJ underlying the facilitation and/or inhibition of temporal resolution in humans.
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Affiliation(s)
- Masakazu Ide
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Takeshi Atsumi
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan.,Department of Medical Physiology, Faculty of Medicine, Kyorin University, Tokyo, Japan
| | - Mrinmoy Chakrabarty
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Department of Social Sciences and Humanities, Indraprastha Institute of Information Technology (IIIT-D), New Delhi, India
| | - Ayako Yaguchi
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan.,Department of Contemporary Psychology, Rikkyo University, Saitama, Japan
| | - Yumi Umesawa
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Department of Medical Physiology, Faculty of Medicine, Kyorin University, Tokyo, Japan
| | - Reiko Fukatsu
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Makoto Wada
- Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
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Arkhipov AY, Khaziev EF, Skorinkin AI, Bukharaeva EA, Samigullin DV. Enhancement of the Temporal Resolution of Fluorescent Signals Acquired by the Confocal Microscope. Microsc Microanal 2020; 26:204-210. [PMID: 32115011 DOI: 10.1017/s1431927620000148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Here, we describe a method of acquisition of fast fluorescent signals with the help of the laser scanning confocal microscope (LSCM). Our method permits an increase in the temporal resolution of acquired signals. The method is based on LSCM recordings of fast fluorescent signals with the shortest achievable time sweep, which are performed with the help of a proprietary algorithm. A series of recordings is made in multiple steps; at each step, the fluorescent signal is incremented by a time interval smaller than the time sweep of the frame of LSCM. The size of the increment determines the achievable time resolution. The convolution of the recorded images results in a signal with the temporal resolution determined by the chosen time increment. This method was applied to register the change in fluorescence (calcium transient) of calcium dye preloaded into peripheral nerve endings by electrical stimulation of the motor nerve. Calculated parameters of the calcium transient were identical to the parameters obtained earlier with the help of a high-speed camera and photodiode. We conclude that the method described here can be applied for the registration of fast fluorescent signals by LSCM with a high spatial and temporal resolution.
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Affiliation(s)
- Arsenii Y Arkhipov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111Kazan, Russia
- Department of Radiophotonics and Microwave Technologies, Kazan National Research Technical University named after A.N. Tupolev, 420111Kazan, Russia
| | - Eduard F Khaziev
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111Kazan, Russia
- Department of Radiophotonics and Microwave Technologies, Kazan National Research Technical University named after A.N. Tupolev, 420111Kazan, Russia
- Open Laboratory of Neuropharmacology, Kazan Federal University, 420111Kazan, Russia
| | - Andrey I Skorinkin
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111Kazan, Russia
| | - Ellya A Bukharaeva
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111Kazan, Russia
| | - Dmitry V Samigullin
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111Kazan, Russia
- Department of Radiophotonics and Microwave Technologies, Kazan National Research Technical University named after A.N. Tupolev, 420111Kazan, Russia
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LaRocco J, Paeng DG. Optimizing Computer-Brain Interface Parameters for Non-invasive Brain-to-Brain Interface. Front Neuroinform 2020; 14:1. [PMID: 32116625 PMCID: PMC7020695 DOI: 10.3389/fninf.2020.00001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/07/2020] [Indexed: 11/29/2022] Open
Abstract
A non-invasive, brain-to-brain interface (BBI) requires precision neuromodulation and high temporal resolution as well as portability to increase accessibility. A BBI is a combination of the brain-computer interface (BCI) and the computer-brain interface (CBI). The optimization of BCI parameters has been extensively researched, but CBI has not. Parameters taken from the BCI and CBI literature were used to simulate a two-class medical monitoring BBI system under a wide range of conditions. BBI function was assessed using the information transfer rate (ITR), measured in bits per trial and bits per minute. The BBI ITR was a function of classifier accuracy, window update rate, system latency, stimulation failure rate (SFR), and timeout threshold. The BCI parameters, including window length, update rate, and classifier accuracy, were kept constant to investigate the effects of varying the CBI parameters, including system latency, SFR, and timeout threshold. Based on passively monitoring BCI parameters, a base ITR of 1 bit/trial was used. The optimal latency was found to be 100 ms or less, with a threshold no more than twice its value. With the optimal latency and timeout parameters, the system was able to maintain near-maximum efficiency, even with a 25% SFR. When the CBI and BCI parameters are compared, the CBI's system latency and timeout threshold should be reflected in the BCI's update rate. This would maximize the number of trials, even at a high SFR. These findings suggested that a higher number of trials per minute optimizes the ITR of a non-invasive BBI. The delays innate to each BCI protocol and CBI stimulation method must also be accounted for. The high latencies in each are the primary constraints of non-invasive BBI for the foreseeable future.
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Affiliation(s)
| | - Dong-Guk Paeng
- Laboratory of Biomedical Ultrasound, Department of Ocean System Engineering, Jeju National University, Jeju City, South Korea
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Brinken L, Schüz B, Ferguson SG, Scholz U, Schüz N. Social cognitions and smoking behaviour: Temporal resolution matters. Br J Health Psychol 2019; 25:210-227. [PMID: 31814262 DOI: 10.1111/bjhp.12402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 11/20/2019] [Indexed: 11/28/2022]
Abstract
Objectives Health behaviour theories outline how cognitions predict behaviours, but rarely specify the temporal relation between cognitions and behaviours. It is not known whether these predictive relationships vary depending on temporal resolution or whether the relative influence of cognitions varies with measurement schedules. The current exploratory study therefore investigates whether the associations between behavioural cognitions (self-efficacy, intention, and risk perception) and smoking vary when measured momentarily, at day level, or using the more common baseline-follow-up design. Design EMA study involving 36 continuing smokers over 17 days. Participants logged cigarettes and reported their cognitions at baseline, daily (evening), and in response to momentary surveys. Methods Random-effects models were used to compare the effects of cognitions measured at different time points on (1) the number of cigarettes smoked daily and (2) the time interval until the next cigarette smoked. Results Self-efficacy and risk perception measured at baseline significantly predicted cigarettes smoked each day, but this effect became non-significant when daily measurements of cognitions were included in the model. Momentary smoking behaviour was predicted by momentary measurements of risk perception, with no significant effects of social cognitions at baseline. Conclusions Relationships between cognitions and behaviours vary according to the temporal resolution of the measurement schedule. Ensuring that the temporal resolution of assessment is appropriate for the temporal dynamics of the behaviour being assessed is important. Future research is needed to investigate the potential for leveraging specific cognitive processes depending on temporal importance in order to increase health-promoting behaviours. Statement of contribution What is already known on this subject? Social cognitions including intentions, risk perception, and self-efficacy have been observed to predict smoking. Little is known about the role of time in the cognition-behaviour relationship. Cognitions have been observed to fluctuate, but instability is typically not considered in research design. What does this study add? Daily measurement of social cognitions predicts behaviour better than measurements taken at baseline. Momentary smoking behaviour is predicted by momentary cognitions at the intra-individual level. Temporal resolution of measurement should be considered when investigating cognition-behaviour relationships.
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Affiliation(s)
- Lillian Brinken
- College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Benjamin Schüz
- College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia.,Institute of Public Health and Nursing Research, University of Bremen, Germany
| | - Stuart G Ferguson
- College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Urte Scholz
- Institute of Psychology, University of Zurich, Switzerland
| | - Natalie Schüz
- College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia.,Deutsche Rentenversicherung Oldenburg, Bremen, Germany
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Khani A, Mustafar F, Rainer G. Distinct Frequency Specialization for Detecting Dark Transients in Humans and Tree Shrews. Cell Rep 2019; 23:2405-2415. [PMID: 29791851 DOI: 10.1016/j.celrep.2018.04.076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 02/23/2018] [Accepted: 04/13/2018] [Indexed: 10/16/2022] Open
Abstract
Despite well-known privileged perception of dark over light stimuli, it is unknown to what extent this dark dominance is maintained when visual transients occur in rapid succession, for example, during perception of moving stimuli. Here, we address this question using dark and light transients presented at different flicker frequencies. Although both human participants and tree shrews exhibited dark dominance for temporally modulated transients, these occurred at different flicker frequencies, namely, at 11 Hz in humans and 40 Hz and higher in tree shrews. Tree shrew V1 neuronal activity confirmed that differences between light and dark flicker were maximal at 40 Hz, corresponding closely to behavioral findings. These findings suggest large differences in flicker perception between humans and tree shrews, which may be related to the lifestyle of these species. A specialization for detecting dark transients at high temporal frequencies may thus be adaptive for tree shrews, which are particularly fast-moving small mammals.
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Affiliation(s)
- Abbas Khani
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, 1700 Fribourg, Switzerland; Functional Brain Mapping Laboratory, Department of Basic Neurosciences, University of Geneva, 1211 Geneva, Switzerland.
| | - Faiz Mustafar
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, 1700 Fribourg, Switzerland; Department of Neurosciences, Universiti Sains Malaysia, 16150 Kelantan, Malaysia
| | - Gregor Rainer
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, 1700 Fribourg, Switzerland.
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Merganičová K, Merganič J, Lehtonen A, Vacchiano G, Sever MZO, Augustynczik ALD, Grote R, Kyselová I, Mäkelä A, Yousefpour R, Krejza J, Collalti A, Reyer CPO. Forest carbon allocation modelling under climate change. Tree Physiol 2019; 39:1937-1960. [PMID: 31748793 PMCID: PMC6995853 DOI: 10.1093/treephys/tpz105] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/03/2019] [Accepted: 09/24/2019] [Indexed: 05/19/2023]
Abstract
Carbon allocation plays a key role in ecosystem dynamics and plant adaptation to changing environmental conditions. Hence, proper description of this process in vegetation models is crucial for the simulations of the impact of climate change on carbon cycling in forests. Here we review how carbon allocation modelling is currently implemented in 31 contrasting models to identify the main gaps compared with our theoretical and empirical understanding of carbon allocation. A hybrid approach based on combining several principles and/or types of carbon allocation modelling prevailed in the examined models, while physiologically more sophisticated approaches were used less often than empirical ones. The analysis revealed that, although the number of carbon allocation studies over the past 10 years has substantially increased, some background processes are still insufficiently understood and some issues in models are frequently poorly represented, oversimplified or even omitted. Hence, current challenges for carbon allocation modelling in forest ecosystems are (i) to overcome remaining limits in process understanding, particularly regarding the impact of disturbances on carbon allocation, accumulation and utilization of nonstructural carbohydrates, and carbon use by symbionts, and (ii) to implement existing knowledge of carbon allocation into defence, regeneration and improved resource uptake in order to better account for changing environmental conditions.
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Affiliation(s)
- Katarína Merganičová
- Czech University of Life Sciences, Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 16500 Praha-Suchdol, Czech Republic
- Technical University Zvolen, Forestry Faculty, T. G. Masaryka 24, 96053 Zvolen, Slovakia
| | - Ján Merganič
- Technical University Zvolen, Forestry Faculty, T. G. Masaryka 24, 96053 Zvolen, Slovakia
| | - Aleksi Lehtonen
- The Finnish Forest Research Institute - Luke, PO Box 18 (Jokiniemenkuja 1), FI-01301 Vantaa, Finland
| | - Giorgio Vacchiano
- Università degli Studi di Milano, DISAA. Via Celoria 2, 20132 Milano, Italy
| | - Maša Zorana Ostrogović Sever
- Croatian Forest Research Institute, Department for forest management and forestry economics, Cvjetno naselje 41, 10450 Jastrebarsko, Croatia
| | | | - Rüdiger Grote
- Institute of Meteorology and Climate Research (IMK-IFU), Karlsruhe Institute of Technology, Garmisch-Partenkirchen, Germany
| | - Ina Kyselová
- Global Change Research Institute CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic
| | - Annikki Mäkelä
- University of Helsinki, Department of Forest Science, Latokartanonkaari 7, P.O. Box 27, 00014 Helsinki, Finland
| | - Rasoul Yousefpour
- University of Freiburg, Tennenbacher Str. 4 (2. OG), D-79106 Freiburg, Germany
| | - Jan Krejza
- Global Change Research Institute CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic
| | - Alessio Collalti
- National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean (CNR-ISAFOM), 87036 Rende, Italy
- Department of Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, 01100 Viterbo, Italy
| | - Christopher P O Reyer
- Potsdam Institute for Climate Impact Research, Telegraphenberg, PO Box 601203, D-14473 Potsdam, Germany
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Shim HJ, Go G, Lee H, Choi SW, Won JH. Influence of Visual Deprivation on Auditory Spectral Resolution, Temporal Resolution, and Speech Perception. Front Neurosci 2019; 13:1200. [PMID: 31780886 PMCID: PMC6851016 DOI: 10.3389/fnins.2019.01200] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/23/2019] [Indexed: 11/23/2022] Open
Abstract
We evaluated whether blind subjects have advantages in auditory spectral resolution, temporal resolution, and speech perception in noise compared with sighted subjects. We also compared psychoacoustic performance between early blind (EB) subjects and late blind (LB) subjects. Nineteen EB subjects, 16 LB subjects, and 20 sighted individuals were enrolled. All subjects were right-handed with normal and symmetric hearing thresholds and without cognitive impairments. Three psychoacoustic measurements of the subjects’ right ears were performed via an inserted earphone to determine spectral-ripple discrimination (SRD), temporal modulation detection (TMD), and speech recognition threshold (SRT) in noisy conditions. Acoustic change complex (ACC) responses were recorded during passive listening to standard ripple-inverted ripple stimuli. EB subjects exhibited better SRD than did LB (p = 0.020) and sighted (p = 0.003) subjects. TMD was better in EB (p < 0.001) and LB (p = 0.007) subjects compared with sighted subjects. SRD was positively correlated with the duration of blindness (r = 0.386, p = 0.024). Acoustic change complex data for ripple noise change at the Cz and Fz electrodes showed trends toward significant correlations with the behavioral results. In conclusion, compared with sighted subjects, EB subjects showed advantages in terms of auditory spectral and temporal resolution, while LB subjects showed an advantage in temporal resolution exclusively. These findings suggest that it might take longer for auditory spectral resolution to functionally enhance following visual deprivation compared to temporal resolution. Alternatively, a critical period of very young age may be required for auditory spectral resolution to improve following visual deprivation.
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Affiliation(s)
- Hyun Joon Shim
- Department of Otorhinolaryngology-Head and Neck Surgery, Eulji Medical Center, Eulji University School of Medicine, Seoul, South Korea
| | - Geurim Go
- Department of Psychology, Duksung Women's University, Seoul, South Korea
| | - Heirim Lee
- Department of Psychology, Duksung Women's University, Seoul, South Korea
| | - Sung Won Choi
- Department of Psychology, Duksung Women's University, Seoul, South Korea
| | - Jong Ho Won
- Division of ENT, Sleep Disordered Breathing, Respiratory, and Anesthesia, Office of Product Evaluation and Quality, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
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Lyatun S, Zverev D, Ershov P, Lyatun I, Konovalov O, Snigireva I, Snigirev A. X-ray reflecto-interferometer based on compound refractive lenses. J Synchrotron Radiat 2019; 26:1572-1581. [PMID: 31490146 PMCID: PMC6730623 DOI: 10.1107/s1600577519007896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 06/01/2019] [Indexed: 06/10/2023]
Abstract
An X-ray amplitude-splitting interferometer based on compound refractive lenses, which operates in the reflection mode, is proposed and realized. The idea of a reflecto-interferometer is to use a very simplified experimental setup where a focused X-ray beam reflected from parallel flat surfaces creates an interference pattern in a wide angular range. The functional capabilities of the interferometer were experimentally tested at the European Synchrotron Radiation Facility (ESRF) ID06 beamline in the X-ray energy range from 10 keV to 15 keV. The main features of the proposed approach, high spatial and temporal resolution, were demonstrated experimentally. The reflections from free-standing Si3N4 membranes, gold and resist layers were studied. Experimentally recorded interferograms are in good agreement with our simulations. The main advantages and future possible applications of the reflecto-interferometer are discussed.
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Affiliation(s)
- S. Lyatun
- Immanuel Kant Baltic Federal University, 14 Nevskogo, 236041 Kaliningrad, Russian Federation
| | - D. Zverev
- Immanuel Kant Baltic Federal University, 14 Nevskogo, 236041 Kaliningrad, Russian Federation
| | - P. Ershov
- Immanuel Kant Baltic Federal University, 14 Nevskogo, 236041 Kaliningrad, Russian Federation
| | - I. Lyatun
- Immanuel Kant Baltic Federal University, 14 Nevskogo, 236041 Kaliningrad, Russian Federation
| | - O. Konovalov
- European Synchrotron Radiation Facility, 71 avenue des Martyrs, 38043 Grenoble, France
| | - I. Snigireva
- European Synchrotron Radiation Facility, 71 avenue des Martyrs, 38043 Grenoble, France
| | - A. Snigirev
- Immanuel Kant Baltic Federal University, 14 Nevskogo, 236041 Kaliningrad, Russian Federation
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Znotinas KR, Standen EM. Aerial and aquatic visual acuity of the grey bichir Polypterus senegalus, as estimated by optokinetic response. J Fish Biol 2019; 95:263-273. [PMID: 29956322 DOI: 10.1111/jfb.13724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/08/2018] [Indexed: 06/08/2023]
Abstract
The present study assessed the aerial and aquatic visual abilities of juvenile grey bichir Polypterus senegalus, fish capable of terrestrial locomotion, by measuring the optokinetic response to stimuli of varying speed and spatial frequency. In water, fish tracked slow-moving (2° s-1 ) stimuli moderately well and fast-moving stimuli very poorly. Spatial acuity was very low compared with many other species, with maximum response observed at 0.05-0.075 stimulus cycles per degree of visual arc; however, it should be noted that adult fish, with their larger eyes, are likely to have somewhat improved spatial acuity. Low spatial acuity and limited stimulus tracking ability might be expected in a nocturnal ambush predator such as P. senegalus, where gaze stabilization may be less crucial and other sensory inputs may have greater importance in perception of the environment. In air, spatial and temporal acuity were both poorer by every measure, but some visual ability persisted. As the eye shows no anatomical specialization for aerial vision, poor vision was expected; however, the large decrease in saccade velocity observed in air trials was unexpected. Stimulus parameters typically have little effect on the characteristics of the saccade, so this finding may suggest that the function of the reflex system itself could be compromised in the aerial vision of some fishes capable of terrestrial locomotion.
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Parent B, Millet EJ, Tardieu F. The use of thermal time in plant studies has a sound theoretical basis provided that confounding effects are avoided. J Exp Bot 2019; 70:2359-2370. [PMID: 31091318 DOI: 10.1093/jxb/ery402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
The use of thermal time is essential in plant studies and crop growth modeling because correcting time for temperature allows working in fluctuating conditions as if temperature was constant. However, thermal time is often seen as a loose concept because of a multitude of thermal functions and case-specific parameter values. Our hypothesis is that these different formalisms and parameterization could emerge from common principles and a common response of plant development to temperature, but with several counfounding factors which are not taken into account. We first show that these calculations of thermal time are based on sound common principles and mathematical formalisms. We test, via a modelling exercise of nine case studies using maize plants grown in three field sites, how a given "ground truth" response of plant development rate to temperature can be affected if an experimenter either considers or ignores confounding factors. We also show that apparent differences in temperature responses between phenological stages of the growth cycle, between day and night, or between plant genotypes may be due to the confounding effects of evaporative demand, the range of temperatures, and the time interval at which measurements are taken. On the basis of our findings, we propose that the critical point in the use of a given formalism of thermal time calculation is to ensure that the chosen model is compatible with the temporal definition, temperature range, and environmental scenario in the considered dataset.
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Affiliation(s)
- Boris Parent
- LEPSE, Université Montpellier, INRA, Montpellier SupAgro, Montpellier, France
| | - Emilie J Millet
- LEPSE, Université Montpellier, INRA, Montpellier SupAgro, Montpellier, France
| | - François Tardieu
- LEPSE, Université Montpellier, INRA, Montpellier SupAgro, Montpellier, France
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Abstract
Epilepsy is a common neurological disease characterized by recurrent unpredictable seizures. For the last 30 years, microdialysis sampling has been used to measure changes in excitatory and inhibitory neurotransmitter concentrations before, during, and after seizures. These advances have fostered breakthroughs in epilepsy research by identifying neurochemical changes associated with seizures and correlating them to electrophysiological data. Recent advances in methodology may be useful in further delineating the chemical underpinnings of seizures. A new model of ictogenesis has been developed that allows greater control over the timing of seizures that are similar to spontaneous seizures. This model will facilitate making chemical measurements before and during a seizure. Recent advancements in microdialysis sampling, including the use of segmented flow, "fast" liquid chromatography (LC), and capillary electrophoresis with laser-induced fluorescence (CE-LIF) have significantly improved temporal resolution to better than 1 min, which could be used to measure transient, spontaneous neurochemical changes associated with seizures. Microfabricated sampling probes that are markedly smaller than conventional probes and allow for a much greater spatial resolution have been developed. They may allow the targeting of specific brain regions important to epilepsy studies. Coupling microdialysis sampling to optogenetics and light-stimulated release of neurotransmitters may also prove useful for studying epileptic seizures.
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Affiliation(s)
- Alexander G. Zestos
- Department of Chemistry, Center for Behavioral Neuroscience, American University, Washington, D.C. 20016, United States
| | - Hiram Luna-Munguia
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, Queretaro 76230, Mexico
| | - William C. Stacey
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Robert T. Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
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Reynolds SM, Gifford RH. Effect of signal processing strategy and stimulation type on speech and auditory perception in adult cochlear implant users. Int J Audiol 2019; 58:363-372. [PMID: 30987476 DOI: 10.1080/14992027.2019.1580390] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE The objective of this study was to investigate the effects of signal processing strategy on speech understanding and auditory function for adult cochlear implant (CI) users with a focus on the effects of sequential versus paired stimulation. DESIGN Within-subjects, repeated measures design was utilised to compare performance between processing strategies and stimulation type on various measures of auditory function and subjective sound quality. Testing with subsequent strategies was completed after a total familiarisation time of two weeks. STUDY SAMPLE Ten post-lingually deafened adult CI users were recruited from a clinical population. Participants had a minimum of 13 months CI experience. Ages ranged from 25-78 years. All participants had long-term experience with the optima strategy; eight with sequential stimulation and two with paired stimulation. RESULTS We found no statistically significant effect of processing strategy. We observed an effect of stimulation type with sequential stimulation yielding significantly higher performance than paired stimulation for speech understanding in quiet and in noise, and subjective estimates of sound quality. No significant differences were noted across strategy or stimulation for music perception, spectral resolution or temporal resolution. CONCLUSIONS Many patients utilise paired stimulation - the default stimulation type in the clinical software; however, sequential stimulation yielded significantly higher outcomes on multiple measures.
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Affiliation(s)
- Susan M Reynolds
- a Department of Hearing and Speech Sciences , Vanderbilt University Medical Center, Vanderbilt Bill Wilkerson Center , Nashville , TN , USA
| | - René H Gifford
- a Department of Hearing and Speech Sciences , Vanderbilt University Medical Center, Vanderbilt Bill Wilkerson Center , Nashville , TN , USA
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48
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Umino Y, Guo Y, Chen CK, Pasquale R, Solessio E. Rod Photoresponse Kinetics Limit Temporal Contrast Sensitivity in Mesopic Vision. J Neurosci 2019; 39:3041-56. [PMID: 30737308 DOI: 10.1523/JNEUROSCI.1404-18.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 11/21/2022] Open
Abstract
The mammalian visual system operates over an extended range of ambient light levels by switching between rod and cone photoreceptors. Rod-driven vision is sluggish, highly sensitive, and operates in dim or scotopic lights, whereas cone-driven vision is brisk, less sensitive, and operates in bright or photopic lights. At intermediate or mesopic lights, vision transitions seamlessly from rod-driven to cone-driven, despite the profound differences in rod and cone response dynamics. The neural mechanisms underlying such a smooth handoff are not understood. Using an operant behavior assay, electrophysiological recordings, and mathematical modeling we examined the neural underpinnings of the mesopic visual transition in mice of either sex. We found that rods, but not cones, drive visual sensitivity to temporal light variations over much of the mesopic range. Surprisingly, speeding up rod photoresponse recovery kinetics in transgenic mice improved visual sensitivity to slow temporal variations, in the range where perceptual sensitivity is governed by Weber's law of sensation. In contrast, physiological processes acting downstream from phototransduction limit sensitivity to high frequencies and temporal resolution. We traced the paradoxical control of visual temporal sensitivity to rod photoresponses themselves. A scenario emerges where perceptual sensitivity is limited by: (1) the kinetics of neural processes acting downstream from phototransduction in scotopic lights, (2) rod response kinetics in mesopic lights, and (3) cone response kinetics as light levels rise into the photopic range.SIGNIFICANCE STATEMENT Our ability to detect flickering lights is constrained by the dynamics of the slowest step in the visual pathway. Cone photoresponse kinetics limit visual temporal sensitivity in bright (photopic) lights, whereas mechanisms in the inner retina limit sensitivity in dim (scotopic) lights. The neural mechanisms underlying the transition between scotopic and photopic vision in mesopic lights, when both rods are cones are active, are unknown. This study provides a missing link in this mechanism by establishing that rod photoresponse kinetics limit temporal sensitivity during the mesopic transition. Surprisingly, this range is where Weber's Law of Sensation governs temporal contrast sensitivity in mouse. Our results will help guide future studies of complex and dynamic interactions between rod-cone signals in the mesopic retina.
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Abstract
Substantial loss of cochlear function is required to elevate pure-tone thresholds to the severe hearing loss range; yet, individuals with severe or profound hearing loss continue to rely on hearing for communication. Despite the impairment, sufficient information is encoded at the periphery to make acoustic hearing a viable option. However, the probability of significant cochlear and/or neural damage associated with the loss has consequences for sound perception and speech recognition. These consequences include degraded frequency selectivity, which can be assessed with tests including psychoacoustic tuning curves and broadband rippled stimuli. Because speech recognition depends on the ability to resolve frequency detail, a listener with severe hearing loss is likely to have impaired communication in both quiet and noisy environments. However, the extent of the impairment varies widely among individuals. A better understanding of the fundamental abilities of listeners with severe and profound hearing loss and the consequences of those abilities for communication can support directed treatment options in this population.
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Affiliation(s)
- Pamela Souza
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois
| | - Eric Hoover
- Department of Hearing and Speech Sciences, University of Maryland, Baltimore, Maryland
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50
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Günel B, Thiel CM, Hildebrandt KJ. Effects of Exogenous Auditory Attention on Temporal and Spectral Resolution. Front Psychol 2018; 9:1984. [PMID: 30405479 PMCID: PMC6206225 DOI: 10.3389/fpsyg.2018.01984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/27/2018] [Indexed: 11/25/2022] Open
Abstract
Previous research in the visual domain suggests that exogenous attention in form of peripheral cueing increases spatial but lowers temporal resolution. It is unclear whether this effect transfers to other sensory modalities. Here, we tested the effects of exogenous attention on temporal and spectral resolution in the auditory domain. Eighteen young, normal-hearing adults were tested in both gap and frequency change detection tasks with exogenous cuing. Benefits of valid cuing were only present in the gap detection task while costs of invalid cuing were observed in both tasks. Our results suggest that exogenous attention in the auditory system improves temporal resolution without compromising spectral resolution.
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Affiliation(s)
- Basak Günel
- Department of Psychology, University of Oldenburg, Oldenburg, Germany
| | - Christiane M Thiel
- Department of Psychology, University of Oldenburg, Oldenburg, Germany.,Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany
| | - K Jannis Hildebrandt
- Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany.,Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
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