1
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Herrera B, Sajad A, Errington SP, Schall JD, Riera JJ. Cortical origin of theta error signals. Cereb Cortex 2023; 33:11300-11319. [PMID: 37804250 PMCID: PMC10690871 DOI: 10.1093/cercor/bhad367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 10/09/2023] Open
Abstract
A multi-scale approach elucidated the origin of the error-related-negativity (ERN), with its associated theta-rhythm, and the post-error-positivity (Pe) in macaque supplementary eye field (SEF). Using biophysical modeling, synaptic inputs to a subpopulation of layer-3 (L3) and layer-5 (L5) pyramidal cells (PCs) were optimized to reproduce error-related spiking modulation and inter-spike intervals. The intrinsic dynamics of dendrites in L5 but not L3 error PCs generate theta rhythmicity with random phases. Saccades synchronized the phases of the theta-rhythm, which was magnified on errors. Contributions from error PCs to the laminar current source density (CSD) observed in SEF were negligible and could not explain the observed association between error-related spiking modulation in L3 PCs and scalp-EEG. CSD from recorded laminar field potentials in SEF was comprised of multipolar components, with monopoles indicating strong electro-diffusion, dendritic/axonal electrotonic current leakage outside SEF, or violations of the model assumptions. Our results also demonstrate the involvement of secondary cortical regions, in addition to SEF, particularly for the later Pe component. The dipolar component from the observed CSD paralleled the ERN dynamics, while the quadrupolar component paralleled the Pe. These results provide the most advanced explanation to date of the cellular mechanisms generating the ERN.
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Affiliation(s)
- Beatriz Herrera
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, United States
| | - Amirsaman Sajad
- Department of Psychology, Vanderbilt Vision Research Center, Center for Integrative & Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37203, United States
| | - Steven P Errington
- Department of Psychology, Vanderbilt Vision Research Center, Center for Integrative & Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37203, United States
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Jeffrey D Schall
- Centre for Vision Research, Vision: Science to Applications Program, Departments of Biology and Psychology, York University, Toronto, ON M3J 1P3, Canada
| | - Jorge J Riera
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, United States
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2
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Morales-Gregorio A, van Meegen A, van Albada SJ. Ubiquitous lognormal distribution of neuron densities in mammalian cerebral cortex. Cereb Cortex 2023; 33:9439-9449. [PMID: 37409647 PMCID: PMC10438924 DOI: 10.1093/cercor/bhad160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 07/07/2023] Open
Abstract
Numbers of neurons and their spatial variation are fundamental organizational features of the brain. Despite the large corpus of cytoarchitectonic data available in the literature, the statistical distributions of neuron densities within and across brain areas remain largely uncharacterized. Here, we show that neuron densities are compatible with a lognormal distribution across cortical areas in several mammalian species, and find that this also holds true within cortical areas. A minimal model of noisy cell division, in combination with distributed proliferation times, can account for the coexistence of lognormal distributions within and across cortical areas. Our findings uncover a new organizational principle of cortical cytoarchitecture: the ubiquitous lognormal distribution of neuron densities, which adds to a long list of lognormal variables in the brain.
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Affiliation(s)
- Aitor Morales-Gregorio
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA-Institut Brain Structure-Function Relationships (INM-10), Jülich Research Centre, Wilhelm-Johnen-Str., 52428 Jülich, Germany
- Institute of Zoology, University of Cologne, Zülpicher Str., 50674 Cologne, Germany
| | - Alexander van Meegen
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA-Institut Brain Structure-Function Relationships (INM-10), Jülich Research Centre, Wilhelm-Johnen-Str., 52428 Jülich, Germany
- Institute of Zoology, University of Cologne, Zülpicher Str., 50674 Cologne, Germany
| | - Sacha J van Albada
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA-Institut Brain Structure-Function Relationships (INM-10), Jülich Research Centre, Wilhelm-Johnen-Str., 52428 Jülich, Germany
- Institute of Zoology, University of Cologne, Zülpicher Str., 50674 Cologne, Germany
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3
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Ocklenburg S, El Basbasse Y, Ströckens F, Müller-Alcazar A. Hemispheric asymmetries and brain size in mammals. Commun Biol 2023; 6:521. [PMID: 37188844 DOI: 10.1038/s42003-023-04894-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/02/2023] [Indexed: 05/17/2023] Open
Abstract
Hemispheric asymmetries differ considerably across species, but the neurophysiological base of this variation is unclear. It has been suggested that hemispheric asymmetries evolved to bypass interhemispheric conduction delay when performing time-critical tasks. This implies that large brains should be more asymmetric. We performed preregistered cross-species meta-regressions with brain mass and neuron number as predictors for limb preferences, a behavioral marker of hemispheric asymmetries, in mammals. Brain mass and neuron number showed positive associations with rightward limb preferences but negative associations with leftward limb preferences. No significant associations were found for ambilaterality. These results are only partly in line with the idea that conduction delay is the critical factor that drives the evolution of hemispheric asymmetries. They suggest that larger-brained species tend to shift towards more right-lateralized individuals. Therefore, the need for coordination of lateralized responses in social species needs to be considered in the context of the evolution of hemispheric asymmetries.
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Affiliation(s)
- Sebastian Ocklenburg
- Department of Psychology, MSH Medical School Hamburg, Hamburg, Germany.
- Institute for Cognitive and Affective Neuroscience, MSH Medical School Hamburg, Hamburg, Germany.
- Biopsychology, Institute for Cognitive Neuroscience, Ruhr University Bochum, Bochum, Germany.
| | - Yasmin El Basbasse
- Biopsychology, Institute for Cognitive Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Felix Ströckens
- C. & O. Vogt Institute for Brain Research, University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Anett Müller-Alcazar
- Department of Psychology, MSH Medical School Hamburg, Hamburg, Germany
- Institute for Cognitive and Affective Neuroscience, MSH Medical School Hamburg, Hamburg, Germany
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4
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Fu Z, Sajad A, Errington SP, Schall JD, Rutishauser U. Neurophysiological mechanisms of error monitoring in human and non-human primates. Nat Rev Neurosci 2023; 24:153-172. [PMID: 36707544 PMCID: PMC10231843 DOI: 10.1038/s41583-022-00670-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2022] [Indexed: 01/29/2023]
Abstract
Performance monitoring is an important executive function that allows us to gain insight into our own behaviour. This remarkable ability relies on the frontal cortex, and its impairment is an aspect of many psychiatric diseases. In recent years, recordings from the macaque and human medial frontal cortex have offered a detailed understanding of the neurophysiological substrate that underlies performance monitoring. Here we review the discovery of single-neuron correlates of error monitoring, a key aspect of performance monitoring, in both species. These neurons are the generators of the error-related negativity, which is a non-invasive biomarker that indexes error detection. We evaluate a set of tasks that allows the synergistic elucidation of the mechanisms of cognitive control across the two species, consider differences in brain anatomy and testing conditions across species, and describe the clinical relevance of these findings for understanding psychopathology. Last, we integrate the body of experimental facts into a theoretical framework that offers a new perspective on how error signals are computed in both species and makes novel, testable predictions.
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Affiliation(s)
- Zhongzheng Fu
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Division of Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA.
| | - Amirsaman Sajad
- Center for Integrative & Cognitive Neuroscience, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN, USA
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Steven P Errington
- Center for Integrative & Cognitive Neuroscience, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN, USA
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Jeffrey D Schall
- Center for Integrative & Cognitive Neuroscience, Vanderbilt University, Nashville, TN, USA.
- Department of Psychology, Vanderbilt University, Nashville, TN, USA.
- Centre for Vision Research, York University, Toronto, Ontario, Canada.
- Vision: Science to Applications (VISTA), York University, Toronto, Ontario, Canada.
- Department of Biology, Faculty of Science, York University, Toronto, Ontario, Canada.
| | - Ueli Rutishauser
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
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5
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Zheng H, Zhang X, Tian L, Liu B, He X, Wang L, Ding S, Guo Y, Cai J. Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes with an MT-TL1 m.3243A>G point mutation: Neuroradiological features and their implications for underlying pathogenesis. Front Neurosci 2023; 16:1028762. [PMID: 36685235 PMCID: PMC9853426 DOI: 10.3389/fnins.2022.1028762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/13/2022] [Indexed: 01/07/2023] Open
Abstract
Objective Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is one of the most common inherited mitochondrial disorders. Due to the high clinical and genetic heterogeneity of MELAS, it is still a major challenge for clinicians to accurately diagnose the disease at an early stage. Herein, we evaluated the neuroimaging findings of MELAS with an m.3243A>G mutation in MT-TL1 and analyzed the possible underlying pathogenesis of stroke-like episodes. Materials and methods Fifty-nine imaging studies in 24 patients who had a confirmed genetic diagnosis of m.3243A>G (MT-TL1; tRNA Leu) associated with MELAS were reviewed in our case series. The anatomic location, morphological features, signal/intensity characteristics and temporal evolution of lesions were analyzed on magnetic resonance imaging (MRI), and computed tomography (CT) images. The supplying vessels and metabolite content of the lesions were also evaluated by using MR angiography (MRA)/CT angiography (CTA), and MR spectroscopy (MRS), respectively. Results The lesions were most commonly located in the posterior brain, with 37 (37/59, 63%) in the occipital lobe, 32 (32/59, 54%) in the parietal lobe, and 30 (30/59, 51%) in the temporal lobe. The signal characteristics of the lesions varied and evolved over time. Bilateral basal ganglia calcifications were found in 6 of 9 (67%) patients who underwent CT. Cerebral and cerebellar atrophy were found in 38/59 (64%) and 40/59 (68%) patients, respectively. Lesion polymorphism was found in 37/59 (63%) studies. MRS showed elevated lactate doublet peaks in 9/10 (90%) cases. MRA or CTA revealed that the lesion-related arteries were slightly dilated compared with those of the contralateral side in 4 of 6 (67%) cases. Conclusion The imaging features of MELAS vary depending on the disease stage. Polymorphic lesions in a single imaging examination should be considered a diagnostic clue for MELAS. Stroke-like episodes may be involved in a complex pathogenetic process, including mitochondrial angiopathy, mitochondrial cytopathy, and neuronal excitotoxicity.
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Affiliation(s)
- Helin Zheng
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xuemei Zhang
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Medical Affairs, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Lu Tian
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Bo Liu
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoya He
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Longlun Wang
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Shuang Ding
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Yi Guo
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Pediatric Neurology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China,*Correspondence: Yi Guo,
| | - Jinhua Cai
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China,Jinhua Cai,
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6
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Cai S, Guo Z, Wang X, Huang K, Yuan K, Huang L. Cortical thickness differences are associated with cellular component morphogenesis of astrocytes and excitatory neurons in nonsuicidal self-injuring youth. Cereb Cortex 2023; 33:811-822. [PMID: 35253859 DOI: 10.1093/cercor/bhac103] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 02/03/2023] Open
Abstract
Nonsuicidal self-injury (NSSI) generally occurs in youth and probably progresses to suicide. An examination of cortical thickness differences (ΔCT) between NSSI individuals and controls is crucial to investigate potential neurobiological correlates. Notably, ΔCT are influenced by specific genetic factors, and a large proportion of cortical thinning is associated with the expression of genes that overlap in astrocytes and pyramidal cells. However, in NSSI youth, the mechanisms underlying the relations between the genetic and cell type-specific transcriptional signatures to ΔCT are unclear. Here, we studied the genetic association of ΔCT in NSSI youth by performing a partial least-squares regression (PLSR) analysis of gene expression data and 3D-T1 brain images of 45 NSSI youth and 75 controls. We extracted the top-10 Gene Ontology terms for the enrichment results of upregulated PLS component 1 genes related to ΔCT to conduct the cell-type classification and enrichment analysis. Enrichment of cell type-specific genes shows that cellular component morphogenesis of astrocytes and excitatory neurons accounts for the observed NSSI-specific ΔCT. We validated the main results in independent datasets to verify the robustness and specificity. We concluded that the brain ΔCT is associated with cellular component morphogenesis of astrocytes and excitatory neurons in NSSI youth.
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Affiliation(s)
- Suping Cai
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, PR China
| | - Zitong Guo
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, PR China
| | - Xuwen Wang
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, PR China
| | - Kexin Huang
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, PR China
| | - Kai Yuan
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, PR China.,School of Life Science andTechnology, Xidian University, Engineering Research Center of Molecular and Neuro Imaging Ministry of Education, Xi'an, Shaanxi 710071, PR China.,Information Processing Laboratory, School of Information Engineering, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014010, PR China.,Xi'an Key Laboratory of Intelligent Sensing and Regulation of Trans-Scale Life Information, School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710126, PR China
| | - Liyu Huang
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, PR China
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7
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Jacques C, Jonas J, Colnat-Coulbois S, Maillard L, Rossion B. Low and high frequency intracranial neural signals match in the human associative cortex. eLife 2022; 11:76544. [PMID: 36074548 PMCID: PMC9457683 DOI: 10.7554/elife.76544] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 08/18/2022] [Indexed: 11/13/2022] Open
Abstract
In vivo intracranial recordings of neural activity offer a unique opportunity to understand human brain function. Intracranial electrophysiological (iEEG) activity related to sensory, cognitive or motor events manifests mostly in two types of signals: event-related local field potentials in lower frequency bands (<30 Hz, LF) and broadband activity in the higher end of the frequency spectrum (>30 Hz, High frequency, HF). While most current studies rely exclusively on HF, thought to be more focal and closely related to spiking activity, the relationship between HF and LF signals is unclear, especially in human associative cortex. Here, we provide a large-scale in-depth investigation of the spatial and functional relationship between these 2 signals based on intracranial recordings from 121 individual brains (8000 recording sites). We measure category-selective responses to complex ecologically salient visual stimuli - human faces - across a wide cortical territory in the ventral occipito-temporal cortex (VOTC), with a frequency-tagging method providing high signal-to-noise ratio (SNR) and the same objective quantification of signal and noise for the two frequency ranges. While LF face-selective activity has higher SNR across the VOTC, leading to a larger number of significant electrode contacts especially in the anterior temporal lobe, LF and HF display highly similar spatial, functional, and timing properties. Specifically, and contrary to a widespread assumption, our results point to nearly identical spatial distribution and local spatial extent of LF and HF activity at equal SNR. These observations go a long way towards clarifying the relationship between the two main iEEG signals and reestablish the informative value of LF iEEG to understand human brain function.
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Affiliation(s)
- Corentin Jacques
- Université de Lorraine, CNRS, CRAN, Nancy, France.,Psychological Sciences Research Institute (IPSY), Université Catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
| | - Jacques Jonas
- Université de Lorraine, CNRS, CRAN, Nancy, France.,Université de Lorraine, CHRU-Nancy, Service de Neurologie, Nancy, France
| | | | - Louis Maillard
- Université de Lorraine, CNRS, CRAN, Nancy, France.,Université de Lorraine, CHRU-Nancy, Service de Neurologie, Nancy, France
| | - Bruno Rossion
- Université de Lorraine, CNRS, CRAN, Nancy, France.,Université de Lorraine, CHRU-Nancy, Service de Neurologie, Nancy, France
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8
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Alreja A, Nemenman I, Rozell CJ. Constrained brain volume in an efficient coding model explains the fraction of excitatory and inhibitory neurons in sensory cortices. PLoS Comput Biol 2022; 18:e1009642. [PMID: 35061666 PMCID: PMC8809590 DOI: 10.1371/journal.pcbi.1009642] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/02/2022] [Accepted: 11/14/2021] [Indexed: 11/18/2022] Open
Abstract
The number of neurons in mammalian cortex varies by multiple orders of magnitude across different species. In contrast, the ratio of excitatory to inhibitory neurons (E:I ratio) varies in a much smaller range, from 3:1 to 9:1 and remains roughly constant for different sensory areas within a species. Despite this structure being important for understanding the function of neural circuits, the reason for this consistency is not yet understood. While recent models of vision based on the efficient coding hypothesis show that increasing the number of both excitatory and inhibitory cells improves stimulus representation, the two cannot increase simultaneously due to constraints on brain volume. In this work, we implement an efficient coding model of vision under a constraint on the volume (using number of neurons as a surrogate) while varying the E:I ratio. We show that the performance of the model is optimal at biologically observed E:I ratios under several metrics. We argue that this happens due to trade-offs between the computational accuracy and the representation capacity for natural stimuli. Further, we make experimentally testable predictions that 1) the optimal E:I ratio should be higher for species with a higher sparsity in the neural activity and 2) the character of inhibitory synaptic distributions and firing rates should change depending on E:I ratio. Our findings, which are supported by our new preliminary analyses of publicly available data, provide the first quantitative and testable hypothesis based on optimal coding models for the distribution of excitatory and inhibitory neural types in the mammalian sensory cortices. Neurons in the brain come in two main types: excitatory and inhibitory. The interplay between them shapes neural computation. Despite brain sizes varying by several orders of magnitude across species, the ratio of excitatory and inhibitory sub-populations (E:I ratio) remains relatively constant, and we don’t know why. Simulations of theoretical models of the brain can help answer such questions, especially when experiments are prohibitive or impossible. Here we placed one such theoretical model of sensory coding (’sparse coding’ that minimizes the simultaneously active neurons) under a biophysical ‘volume’ constraint that fixes the total number of neurons available. We vary the E:I ratio in the model (which cannot be done in experiments), and reveal an optimal E:I ratio where the representation of sensory stimulus and energy consumption within the circuit are concurrently optimal. We also show that varying the population sparsity changes the optimal E:I ratio, spanning the relatively narrow ranges observed in biology. Crucially, this minimally parameterized theoretical model makes predictions about structure (recurrent connectivity) and activity (population sparsity) in neural circuits with different E:I ratios (i.e., different species), of which we verify the latter in a first-of-its-kind inter-species comparison using newly publicly available data.
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Affiliation(s)
- Arish Alreja
- Neuroscience Institute, Center for the Neural Basis of Cognition and Machine Learning Department, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Ilya Nemenman
- Department of Physics, Department of Biology and Initiative in Theory and Modeling of Living Systems, Emory University, Atlanta, Georgia, United States of America
| | - Christopher J. Rozell
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * E-mail:
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9
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van Albada SJ, Morales-Gregorio A, Dickscheid T, Goulas A, Bakker R, Bludau S, Palm G, Hilgetag CC, Diesmann M. Bringing Anatomical Information into Neuronal Network Models. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1359:201-234. [DOI: 10.1007/978-3-030-89439-9_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Quezada S, van de Looij Y, Hale N, Rana S, Sizonenko SV, Gilchrist C, Castillo-Melendez M, Tolcos M, Walker DW. Genetic and microstructural differences in the cortical plate of gyri and sulci during gyrification in fetal sheep. Cereb Cortex 2020; 30:6169-6190. [PMID: 32609332 DOI: 10.1093/cercor/bhaa171] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/29/2020] [Accepted: 05/29/2020] [Indexed: 12/28/2022] Open
Abstract
Gyrification of the cerebral cortex is a developmentally important process, but the mechanisms that drive cortical folding are not fully known. Theories propose that changes within the cortical plate (CP) cause gyrification, yet differences between the CP below gyri and sulci have not been investigated. Here we report genetic and microstructural differences in the CP below gyri and sulci assessed before (at 70 days of gestational age [GA] 70), during (GA 90), and after (GA 110) gyrification in fetal sheep. The areal density of BDNF, CDK5, and NeuroD6 immunopositive cells were increased, and HDAC5 and MeCP2 mRNA levels were decreased in the CP below gyri compared with sulci during gyrification, but not before. Only the areal density of BDNF-immunopositive cells remained increased after gyrification. MAP2 immunoreactivity and neurite outgrowth were also increased in the CP below gyri compared with sulci at GA 90, and this was associated with microstructural changes assessed via diffusion tensor imaging and neurite orientation dispersion and density imaging at GA 98. Differential neurite outgrowth may therefore explain the localized changes in CP architecture that result in gyrification.
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Affiliation(s)
- Sebastian Quezada
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC 3168, Australia.,School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083 Australia
| | - Yohan van de Looij
- Division of Development and Growth, Department of Paediatrics and Gynaecology-Obstetrics, School of Medicine, University of Geneva, 1204 Geneva, Switzerland.,Functional and Metabolic Imaging Lab, Federal Institute of Technology of Lausanne, Lausanne 1015, Switzerland
| | - Nadia Hale
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC 3168, Australia
| | - Shreya Rana
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC 3168, Australia
| | - Stéphane V Sizonenko
- Division of Development and Growth, Department of Paediatrics and Gynaecology-Obstetrics, School of Medicine, University of Geneva, 1204 Geneva, Switzerland
| | - Courtney Gilchrist
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083 Australia.,Clinical Sciences, Murdoch Children's Research Institute, Parkville, VIC 3052, Australia
| | - Margie Castillo-Melendez
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC 3168, Australia
| | - Mary Tolcos
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC 3168, Australia.,School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083 Australia
| | - David W Walker
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC 3168, Australia.,School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083 Australia
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11
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Finsterer J. The metabolic hypothesis is more likely than the epileptogenic hypothesis to explain stroke-like lesions. Wellcome Open Res 2020; 5:51. [PMID: 32647751 PMCID: PMC7324943 DOI: 10.12688/wellcomeopenres.15758.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2020] [Indexed: 11/20/2022] Open
Abstract
Stroke-like episodes (SLEs) are a hallmark of mitochondrial encephalopathy, lactic acidosis, and stroke-like episode (MELAS) syndrome but occur in other mitochondrial disorders (MIDs) as well. The morphological equivalent of the SLE is the stroke-like lesion (SLL) on magnetic resonance imaging (MRI). The pathophysiology of SLLs is under debate, but several hypotheses have been raised to explain the phenomenon. Of these, the metabolic, epileptogenic, and vascular hypotheses are the most frequently discussed. There are several arguments for and against these hypotheses, but a consensus has not been reached which of them provides the correct explanation. A recent consensus statement generated by a panel of experts applying the Delphi method, favoured the epileptogenic hypothesis and recommended treatment of SLEs with antiepileptic drugs, irrespective if the patient presented with a seizure or epileptiform discharges on electroencephalography (EEG) or not. We disagree with this general procedure and provide the following arguments against the epileptogenic hypothesis: 1. not each SLE is associated with seizures. 2. epileptiform discharges may be absent on EEG during a SLE. 3. SLLs are not restricted to the cortex. 4. antiseizure-drugs (ASDs) may not prevent the progression or recurrence of a SLL. 5. ASDs may terminate seizures but no other phenotypic feature of a SLE. 6. patients already under ASDs are not immune from developing a SLL. 7. SLLs usually last longer than seizures. 8. no animal model supports the epileptogenic hypothesis. The strongest arguments for the metabolic hypothesis are that SLLs are not confined to a vascular territory, that the oxygen-extraction fraction within a SLL is reduced, and that there is hypometabolism within a SLL on FDG-PET. SLLs may respond to antioxidants, NO-precursors, steroids, or the ketogenic diet. ASDs should be applied only if there is clinical or electrophysiological evidence of seizure-activity.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Messerli Institute, Vienna, 1180, Austria
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12
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Kelly JG, Hawken MJ. GABAergic and non-GABAergic subpopulations of Kv3.1b-expressing neurons in macaque V2 and MT: laminar distributions and proportion of total neuronal population. Brain Struct Funct 2020; 225:1135-1152. [PMID: 32266458 DOI: 10.1007/s00429-020-02065-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 03/27/2020] [Indexed: 11/26/2022]
Abstract
The Kv3.1b potassium channel subunit, which facilitates the fast-spiking phenotype characteristic of parvalbumin (PV)-expressing inhibitory interneurons, is also expressed by subpopulations of excitatory neurons in macaque cortex. We have previously shown that V1 neurons expressing Kv3.1b but not PV or GABA were largely concentrated within layers 4Cα and 4B of V1, suggesting laminar or pathway specificity. In the current study, the distribution and pattern of co-immunoreactivity of GABA, PV, and Kv3.1b across layers in extrastriate cortical areas V2 and MT of the macaque monkey were measured using the same triple immunofluorescence labeling, confocal microscopy, and partially automated cell-counting strategies used in V1. For comparison, densities of the overall cell and neuronal populations were also measured for each layer of V2 and MT using tissue sections immunofluorescence labeled for the pan-neuronal marker NeuN. GABAergic neurons accounted for 14% of the total neuronal population in V2 and 25% in MT. Neurons expressing Kv3.1b but neither GABA nor PV were present in both areas. This subpopulation was most prevalent in the lowest subcompartment of layer 3, comprising 5% of the total neuronal population in layer 3C of both areas, and 41% and 36% of all Kv3.1b+ neurons in this layer in V2 and MT, respectively. The prevalence and laminar distribution of this subpopulation were remarkably consistent between V2 and MT and showed a striking similarity to the patterns observed previously in V1, suggesting a common contribution to the cortical circuit across areas.
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Affiliation(s)
- Jenna G Kelly
- Center for Neural Science, New York University, 4 Washington Place, New York, NY, 10003, USA
| | - Michael J Hawken
- Center for Neural Science, New York University, 4 Washington Place, New York, NY, 10003, USA.
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13
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Finsterer J. The metabolic hypothesis is more likely than the epileptogenic hypothesis to explain stroke-like lesions. Wellcome Open Res 2020; 5:51. [DOI: 10.12688/wellcomeopenres.15758.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2020] [Indexed: 11/20/2022] Open
Abstract
Stroke-like episodes (SLEs) are a hallmark of mitochondrial encephalopathy, lactic acidosis, and stroke-like episode (MELAS) syndrome but occur in other mitochondrial disorders (MIDs) as well. The morphological equivalent of the SLE is the stroke-like lesion (SLL) on magnetic resonance imaging (MRI). The pathophysiology of SLLs is under debate, but several hypotheses have been raised to explain the phenomenon. Of these, the metabolic, epileptogenic, and vascular hypotheses are the most frequently discussed. There are several arguments for and against these hypotheses, but a consensus has not been reached which of them provides the correct explanation. A recent consensus statement generated by a panel of experts applying the Delphi method, favoured the epileptogenic hypothesis and recommended treatment of SLEs with antiepileptic drugs, irrespective if the patient presented with a seizure or epileptiform discharges on electroencephalography (EEG) or not. We disagree with this general procedure and provide the following arguments against the epileptogenic hypothesis: 1. not each SLE is associated with seizures. 2. epileptiform discharges may be absent on EEG during a SLE. 3. SLLs are not restricted to the cortex. 4. antiseizure-drugs (ASDs) may not prevent the progression or recurrence of a SLL. 5. ASDs may terminate seizures but no other phenotypic feature of a SLE. 6. patients already under ASDs are not immune from developing a SLL. 7. SLLs usually last longer than seizures. 8. no animal model supports the epileptogenic hypothesis. The strongest arguments for the metabolic hypothesis are that SLLs are not confined to a vascular territory, that the oxygen-extraction fraction within a SLL is reduced, and that there is hypometabolism within a SLL on FDG-PET. SLLs may respond to antioxidants, NO-precursors, steroids, or the ketogenic diet. ASDs should be applied only if there is clinical or electrophysiological evidence of seizure-activity.
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14
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Bigelow J, Malone B. Extracellular voltage thresholds for maximizing information extraction in primate auditory cortex: implications for a brain computer interface. J Neural Eng 2020; 18. [PMID: 32126540 DOI: 10.1088/1741-2552/ab7c19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/03/2020] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Research by Oby et al (2016) demonstrated that the optimal threshold for extracting information from visual and motor cortices may differ from the optimal threshold for identifying single neurons via spike sorting methods. The optimal threshold for extracting information from auditory cortex has yet to be identified, nor has the optimal temporal scale for representing auditory cortical activity. Here, we describe a procedure to jointly optimize the extracellular threshold and bin size with respect to the decoding accuracy achieved by a linear classifier for a diverse set of auditory stimuli. APPROACH We used linear multichannel arrays to record extracellular neural activity from the auditory cortex of awake squirrel monkeys passively listening to both simple and complex sounds. We executed a grid search of the coordinate space defined by the voltage threshold (in units of standard deviation) and the bin size (in units of milliseconds), and computed decoding accuracy at each point. MAIN RESULTS The optimal threshold for information extraction was consistently near two standard deviations below the voltage trace mean, which falls significantly below the range of three to five standard deviations typically used as inputs to spike sorting algorithms in basic research and in brain-computer interface (BCI) applications. The optimal binwidth was minimized at the optimal voltage threshold, particularly for acoustic stimuli dominated by temporally dynamic features, indicating that permissive thresholding permits readout of cortical responses with temporal precision on the order of a few milliseconds. SIGNIFICANCE The improvements in decoding accuracy we observed for optimal readout parameters suggest that standard thresholding methods substantially underestimate the information present in auditory cortical spiking patterns. The fact that optimal thresholds were relatively low indicates that local populations of cortical neurons exhibit high temporal coherence that could be leveraged in service of future auditory BCI applications.
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Affiliation(s)
- James Bigelow
- OHNS, University of California System, San Francisco, California, UNITED STATES
| | - Brian Malone
- OHNS, University of California System, 675 Nelson Rising Lane (Room 535), University of California San Francisco, San Francisco, San Francisco, California, 94158, UNITED STATES
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15
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Finsterer J, Aliyev R. Metabolic stroke or stroke-like lesion: Peculiarities of a phenomenon. J Neurol Sci 2020; 412:116726. [PMID: 32088469 DOI: 10.1016/j.jns.2020.116726] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/03/2020] [Accepted: 02/06/2020] [Indexed: 01/19/2023]
Abstract
OBJECTIVES One of the most frequent cerebral lesions in mitochondrial disorders(MIDs) on imaging is the stroke-like lesion(SLL) clinically manifesting as stroke-like episode (SLE, metabolic stroke). This review aims at discussing recent advances concerning the presentation, diagnosis, and treatment of SLLs. METHODS Systematic literature review using appropriate search terms. RESULTS SLLs are the hallmark of MELAS but occasionally occur in other MIDs. SLLs are best identified on multimodal, cerebral MRI. SLLs may present as uni-/multilocular, symmetric/asymmetric, cortical/subcortical, supra-/infratentorial condition, initially resembling a cytotoxic edema and later a vasogenic edema, or a variable mix between them. SLLs run through an acute and a chronic stage. The acute stage is characterised by a progressively expanding lesion over days, weeks, or months, showing up as increasing hyperintensity on T2/FLAIR, DWI, and PWI and by hyperperfusion, that does not conform to a vascular territory. ADC maps are initially hypointens to become hyperintens during the course. More rarely, a variable mixture of hyper- and hypointensities may be found. The chronic stage is characterised by hypoperfusion, gadolinium enhancement, and regression of hyperintensities to various endpoints. SLLs originate from an initial cortical lesion due to focal metabolic breakdown, which either remains stable or expands within the cortex or to subcortical areas. Some SLLs show spontaneous reversibility (fleeing cortical lesions) suggesting that neuronal/glial damage does not reach the threshold of irreversible cell death. CONCLUSIONS SLLs are a unique feature of various MIDs in particular MELAS. SLLs are dynamic and change their appearance over time. SLLs are accessible to treatment.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Messerli Institute, Vienna, Austria.
| | - Rahim Aliyev
- Department of Neurology and Clinical Neurophysiology, Azerbaijan State Advanced Training Institute for Doctors named after A. Aliyev, Baku, Azerbaijan
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Němec P, Osten P. The evolution of brain structure captured in stereotyped cell count and cell type distributions. Curr Opin Neurobiol 2020; 60:176-183. [PMID: 31945723 PMCID: PMC7191610 DOI: 10.1016/j.conb.2019.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 12/13/2022]
Abstract
The stereotyped features of brain structure, such as the distribution, morphology and connectivity of neuronal cell types across brain areas, are those most likely to explain the remarkable capacity of the brain to process information and govern behaviors. Recent advances in anatomical methods, including the simple but versatile isotropic fractionator and several whole-brain labeling, clearing and microscopy methods, have opened the door to an exciting new era in comparative brain anatomy, one that has the potential to transform our understanding of the brain structure-function relationship by representing the evolution of brain complexity in quantitative anatomical features shared across species and species-specific or clade-specific. Here we discuss these methods and their application to mapping brain cell count and cell type distributions-two particularly powerful neural correlates of vertebrate cognitive and behavioral capabilities.
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Affiliation(s)
- Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic.
| | - Pavel Osten
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11743, USA.
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Bhatia KD, Krishnan P, Kortman H, Klostranec J, Krings T. Acute Cortical Lesions in MELAS Syndrome: Anatomic Distribution, Symmetry, and Evolution. AJNR Am J Neuroradiol 2019; 41:167-173. [PMID: 31806591 DOI: 10.3174/ajnr.a6325] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/02/2019] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND PURPOSE Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is a rare mitochondrial disorder affecting children and young adults. Stroke-like episodes are often associated with acute cortical lesions in the posterior cerebral cortex and are classically described as asymmetric and transient. In this study we assessed the anatomic distribution of acute cortical lesions, the incidence of symmetry, and the temporal evolution of lesions. MATERIALS AND METHODS This was a retrospective cohort study of patients who had a confirmed genetic diagnosis of a pathogenic variant associated with MELAS and MR imaging performed at our center (2006-2018). Each MR imaging study was assessed for new lesions using T1, T2, FLAIR, DWI, ADC, and SWI. The anatomic location, symmetry, and temporal evolution of lesions were analyzed. RESULTS Eight patients with the same pathogenic variant of MELAS (MT-TL1 m.3243A>G) with 31 MR imaging studies were included. Forty-one new lesions were identified in 17 of the studies (5 deep, 36 cortical). Cortical lesions most commonly affected the primary visual cortex, the middle-third of the primary somatosensory cortex, and the primary auditory cortex. Thirty of 36 cortical lesions had acute cortical diffusion restriction, of which 21 developed cortical laminar necrosis on subacute imaging. Six of 11 studies with multiple lesions showed symmetric cortical involvement. CONCLUSIONS Acute cortical lesions in MELAS most commonly affect the primary visual, somatosensory, and auditory cortices, all regions of high neuronal density and metabolic demand. The most common pattern of temporal evolution is acute cortical diffusion restriction with subacute cortical laminar necrosis and chronic volume loss. Symmetric involvement is more common than previously described.
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Affiliation(s)
- K D Bhatia
- From the Division of Neuroradiology (K.D.B., H.K., J.K., T.K.), Joint Department of Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada
| | - P Krishnan
- Department of Diagnostic Imaging (P.K.), Hospital for Sick Children, Toronto, Ontario, Canada
| | - H Kortman
- From the Division of Neuroradiology (K.D.B., H.K., J.K., T.K.), Joint Department of Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada
| | - J Klostranec
- From the Division of Neuroradiology (K.D.B., H.K., J.K., T.K.), Joint Department of Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada
| | - T Krings
- From the Division of Neuroradiology (K.D.B., H.K., J.K., T.K.), Joint Department of Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada
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18
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Finlay BL, Huang K. Developmental duration as an organizer of the evolving mammalian brain: scaling, adaptations, and exceptions. Evol Dev 2019; 22:181-195. [PMID: 31794147 DOI: 10.1111/ede.12329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neurodevelopmental duration plays a central role in the evolution of the retina and neocortex in mammals. In the diurnal primate eye and retina, it is necessary to scale the number of cones versus the number of rods with different exponents to defend their respective functions of spatial acuity and sensitivity in eyes of different sizes. The order of photoreceptor precursor specification, cones specified first, rods second, couples their respective cell numbers at maturity to the kinetics of embryonic stem cell proliferation. Different durations of retinogenesis change the ratio of rods to cones produced so as to defend both functions over a range of eye diameters. In the evolution of nocturnality, the same coupling of photoreceptor specification to neurogenesis is altered to fewer cones and many more rods in nocturnal eyes, by delaying the onset of retinogenesis. Similarly, the neocortex also shows coupling of the specification of laminar position with duration of neurogenesis. Overall, duration of neurogenesis directly predicts neocortex volume in most mammalian clades. In larger brains with longer neocortical neurogenesis, its organization changes progressively, differentiating the frontal pole from the occipital pole in volume of connectivity and number of neurons per unit column. This permits greater, hierarchically organized information abstraction with increasing neocortex volume. Exceptions do exist, however, in species of three separate taxa, marsupials, naked mole rats, and bats, which break the correlation of neurodevelopmental duration and brain size. Naked mole rats and bats both have small brains and unusual longevity, coupled with neurodevelopmental periods characteristic of much bigger-brained animals, raising the possibility that developmental duration and lifespan have some genetic or mechanistic control in common. The role of duration of development in mediating between the mechanistic levels of construction of retinal and cortical organization, and the different life histories associated with larger brains, such as duration of parental care, learning and overall longevity are discussed.
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Affiliation(s)
- Barbara L Finlay
- Behavioral and Evolutionary Science Group, Department of Psychology, Cornell University, Ithaca, New York
| | - Kexin Huang
- Institute for Advanced Research, Shanghai, China
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Shin J, French L, Xu T, Leonard G, Perron M, Pike GB, Richer L, Veillette S, Pausova Z, Paus T. Cell-Specific Gene-Expression Profiles and Cortical Thickness in the Human Brain. Cereb Cortex 2019; 28:3267-3277. [PMID: 28968835 DOI: 10.1093/cercor/bhx197] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 07/13/2017] [Indexed: 01/25/2023] Open
Abstract
Neurobiological underpinnings of cortical thickness in the human brain are largely unknown. Here we use cell-type-specific gene markers to evaluate the contribution of 9 neural cell-types in explaining inter-regional variations in cortical thickness and age-related cortical thinning in the adolescent brain. Gene-expression data were derived from the Allen Human Brain Atlas (and validated using the BrainSpan Atlas). Values of cortical thickness/thinning were obtained with magnetic resonance imaging in a sample of 987 adolescents. We show that inter-regional profiles in cortical thickness relate to those in the expression of genes marking CA1 pyramidal cells, astrocytes, and microglia; taken together, the 3 cell types explain 70% of regional variation in cortical thickness. We also show that inter-regional profiles in cortical thinning relate to those in the expression of genes marking CA1 and S1 pyramidal cells, astrocytes and microglia. Using Gene Ontology analysis, we demonstrate that the difference in the contribution of CA1 and S1 pyramidal cells may relate to biological processes such as neuronal plasticity and potassium channel activity, respectively. This "virtual histology" approach (scripts provided) can be used to examine neurobiological underpinnings of cortical profiles associated with development, aging, and various disorders.
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Affiliation(s)
- Jean Shin
- The Hospital for Sick Children, University of Toronto, Toronto, Canada.,Rotman Research Institute, University of Toronto, Toronto, Canada
| | - Leon French
- Centre for Addition and Mental Health, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Ting Xu
- Center for Developing Brain, Child Mind Institute, New York, NY, USA
| | - Gabriel Leonard
- Montreal Neurological Institute, McGill University, Montreal, Canada
| | | | - G Bruce Pike
- Departments of Radiology & Clinical Neuroscience, University of Calgary, Calgary, Canada
| | - Louis Richer
- Department of Psychology, University of Quebec in Chicoutimi, Chicoutimi, Canada
| | | | - Zdenka Pausova
- The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Tomáš Paus
- Rotman Research Institute, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada.,Center for Developing Brain, Child Mind Institute, New York, NY, USA.,Department of Psychology, University of Toronto, Toronto,Canada
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Abstract
The sense of touch affords a remarkable sensitivity to the microstructure of surfaces, affording us the ability to sense elements ranging in size from tens of nanometers to tens of millimeters. The hand sends signals about texture to the brain using three classes of nerve fibers through two neural codes: coarse features in spatial patterns of activation and fine features in precise temporal spiking patterns. In this study, we show that these nerve signals culminate in a complex, high-dimensional representation of texture in somatosensory cortex, whose structure can account for the structure of texture perception. This complexity arises from the neurons that act as idiosyncratic detectors of spatial and/or temporal motifs in the afferent input. In the somatosensory nerves, the tactile perception of texture is driven by spatial and temporal patterns of activation distributed across three populations of afferents. These disparate streams of information must then be integrated centrally to achieve a unified percept of texture. To investigate the representation of texture in somatosensory cortex, we scanned a wide range of natural textures across the fingertips of rhesus macaques and recorded the responses evoked in Brodmann’s areas 3b, 1, and 2. We found that texture identity is reliably encoded in the idiosyncratic responses of populations of cortical neurons, giving rise to a high-dimensional representation of texture. Cortical neurons fall along a continuum in their sensitivity to fine vs. coarse texture, and neurons at the extrema of this continuum seem to receive their major input from different afferent populations. Finally, we show that cortical responses can account for several aspects of texture perception in humans.
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Swiegers J, Bhagwandin A, Sherwood CC, Bertelsen MF, Maseko BC, Hemingway J, Rockland KS, Molnár Z, Manger PR. The distribution, number, and certain neurochemical identities of infracortical white matter neurons in a lar gibbon (Hylobates lar) brain. J Comp Neurol 2018; 527:1633-1653. [PMID: 30378128 DOI: 10.1002/cne.24545] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/04/2018] [Accepted: 09/21/2018] [Indexed: 01/08/2023]
Abstract
We examined the number, distribution, and immunoreactivity of the infracortical white matter neuronal population, also termed white matter interstitial cells (WMICs), in the brain of a lesser ape, the lar gibbon. Staining for neuronal nuclear marker (NeuN) revealed WMICs throughout the infracortical white matter, these cells being most numerous and dense close to cortical layer VI, decreasing significantly in density with depth in the white matter. Stereological analysis of NeuN-immunopositive cells revealed a global estimate of ~67.5 million WMICs within the infracortical white matter of the gibbon brain, indicating that the WMICs are a numerically significant population, ~2.5% of the total cortical gray matter neurons that would be estimated for a primate brain the mass of that of the lar gibbon. Immunostaining revealed subpopulations of WMICs containing neuronal nitric oxide synthase (nNOS, ~7 million in number, with both small and large soma volumes), calretinin (~8.6 million in number, all of similar soma volume), very few WMICs containing parvalbumin, and no calbindin-immunopositive neurons. These nNOS, calretinin, and parvalbumin immunopositive WMICs, presumably all inhibitory neurons, represent ~23.1% of the total WMIC population. As the white matter is affected in many cognitive conditions, such as schizophrenia, autism and also in neurodegenerative diseases, understanding these neurons across species is important for the translation of findings of neural dysfunction in animal models to humans. Furthermore, studies of WMICs in species such as apes provide a crucial phylogenetic context for understanding the evolution of these cell types in the human brain.
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Affiliation(s)
- Jordan Swiegers
- Faculty of Health Sciences, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Adhil Bhagwandin
- Faculty of Health Sciences, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia
| | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Busisiwe C Maseko
- Faculty of Health Sciences, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Jason Hemingway
- Faculty of Health Sciences, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Kathleen S Rockland
- Department of Anatomy and Neurobiology, School of Medicine, Boston University, Boston, Massachusetts
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, England
| | - Paul R Manger
- Faculty of Health Sciences, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
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22
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Atapour N, Majka P, Wolkowicz IH, Malamanova D, Worthy KH, Rosa MGP. Neuronal Distribution Across the Cerebral Cortex of the Marmoset Monkey (Callithrix jacchus). Cereb Cortex 2018; 29:3836-3863. [DOI: 10.1093/cercor/bhy263] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 09/13/2018] [Accepted: 09/19/2018] [Indexed: 01/18/2023] Open
Abstract
Abstract
Using stereological analysis of NeuN-stained sections, we investigated neuronal density and number of neurons per column throughout the marmoset cortex. Estimates of mean neuronal density encompassed a greater than 3-fold range, from >150 000 neurons/mm3 in the primary visual cortex to ~50 000 neurons/mm3 in the piriform complex. There was a trend for density to decrease from posterior to anterior cortex, but also local gradients, which resulted in a complex pattern; for example, in frontal, auditory, and somatosensory cortex neuronal density tended to increase towards anterior areas. Anterior cingulate, motor, premotor, insular, and ventral temporal areas were characterized by relatively low neuronal densities. Analysis across the depth of the cortex revealed greater laminar variation of neuronal density in occipital, parietal, and inferior temporal areas, in comparison with other regions. Moreover, differences between areas were more pronounced in the supragranular layers than in infragranular layers. Calculations of the number of neurons per unit column revealed a pattern that was distinct from that of neuronal density, including local peaks in the posterior parietal, superior temporal, precuneate, frontopolar, and temporopolar regions. These results suggest that neuronal distribution in adult cortex result from a complex interaction of developmental/ evolutionary determinants and functional requirements.
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Affiliation(s)
- Nafiseh Atapour
- Neuroscience Program, Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, 770 Blackburn Road, Clayton, Melbourne, VIC, Australia
| | - Piotr Majka
- Neuroscience Program, Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, 770 Blackburn Road, Clayton, Melbourne, VIC, Australia
- Laboratory of Neuroinformatics, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, Warsaw, Poland
| | - Ianina H Wolkowicz
- Neuroscience Program, Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Melbourne, VIC, Australia
| | - Daria Malamanova
- Neuroscience Program, Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Melbourne, VIC, Australia
| | - Katrina H Worthy
- Neuroscience Program, Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Melbourne, VIC, Australia
| | - Marcello G P Rosa
- Neuroscience Program, Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Melbourne, VIC, Australia
- Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, 770 Blackburn Road, Clayton, Melbourne, VIC, Australia
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Imaging microstructure in the living human brain: A viewpoint. Neuroimage 2017; 182:3-7. [PMID: 29024791 DOI: 10.1016/j.neuroimage.2017.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/01/2017] [Accepted: 10/06/2017] [Indexed: 01/06/2023] Open
Abstract
This special issue summarizes an impressive body of work concerned with in vivo imaging of brain microstructure. Collectively, papers included here demonstrate the power of multi-modal magnetic resonance imaging (MRI) for mapping various structural properties of brain tissue. In this introduction, I provide a user's perspective vis-à-vis motivations for these efforts, review briefly the cellular composition of grey and white matter in the human brain, and provide a few examples of how we can bridge the gap between ex vivo and in vivo datasets to facilitate interpretation of studies measuring brain macro- and microstructure.
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Charvet CJ, Stimpson CD, Kim YD, Raghanti MA, Lewandowski AH, Hof PR, Gómez-Robles A, Krienen FM, Sherwood CC. Gradients in cytoarchitectural landscapes of the isocortex: Diprotodont marsupials in comparison to eutherian mammals. J Comp Neurol 2017; 525:1811-1826. [PMID: 28001295 DOI: 10.1002/cne.24160] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 11/26/2016] [Accepted: 12/02/2016] [Indexed: 02/03/2023]
Abstract
Although it has been claimed that marsupials possess a lower density of isocortical neurons compared with other mammals, little is known about cross-cortical variation in neuron distributions in this diverse taxonomic group. We quantified upper-layer (layers II-IV) and lower-layer (layers V-VI) neuron numbers per unit of cortical surface area in three diprotodont marsupial species (two macropodiformes, the red kangaroo and the parma wallaby, and a vombatiform, the koala) and compared these results to eutherian mammals (e.g., xenarthrans, rodents, primates). In contrast to the notion that the marsupial isocortex contains a low density of neurons, we found that neuron numbers per unit of cortical surface area in several marsupial species overlap with those found in eutherian mammals. Furthermore, neuron numbers vary systematically across the isocortex of the marsupial mammals examined. Neuron numbers under a unit of cortical surface area are low toward the frontal cortex and high toward the caudo-medial (occipital) pole. Upper-layer neurons (i.e., layers II-IV) account for most of the variation in neuron numbers across the isocortex. The variation in neuron numbers across the rostral to the caudal pole resembles primates. These findings suggest that diprotodont marsupials and eutherian mammals share a similar cortical architecture despite their distant evolutionary divergence.
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Affiliation(s)
- Christine J Charvet
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
| | - Cheryl D Stimpson
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
| | - Young Do Kim
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
| | - Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, Ohio
| | | | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, Mount Sinai, New York, New York
| | - Aida Gómez-Robles
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
| | - Fenna M Krienen
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
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