1
|
Choi MH, Kim KB, Kim YJ, Kim JS, Kim HS, Yi JH, Chung SC. Changes in the BOLD signal of S1 and BA3 per finger/phalanx as a response to high-frequency vibratory stimulation. Somatosens Mot Res 2024; 41:48-55. [PMID: 36721377 DOI: 10.1080/08990220.2023.2173165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 01/23/2023] [Indexed: 02/02/2023]
Abstract
PURPOSE AND METHOD The purpose of this study was to determine the changes in the Blood Oxygen Level Dependent signal of Primary somatosensory area (S1) and Brodmann area 3 (BA3) per finger and phalanx in comparison to the activation voxel when 250 Hz vibratory stimulation with high sensitivity for the Pacinian corpuscle was given to the four fingers and three phalanges. RESULTS The result of analyzing the activation voxel showed a significant difference for S1 per finger and phalanx, but for BA3, no significant difference was observed despite a similar trend to S1. In contrast, the activation intensity (BOLD) displayed a significant difference for S1 per finger and phalanx and for BA3, where the activation voxel had no significant variation. In addition, while the result of S1 did not indicate whether the index or the little fingers had the highest sensitivity based on the BOLD signal per finger, the result of BA3 marked the strongest BOLD signal for the little finger as a response to 250 Hz vibratory stimulation. The activation intensity per phalanx was the highest for the intermediate phalanx for S1 and BA3, which was in line with a previous study comparing the activation voxel. CONCLUSIONS The method based on the intensity of the nerve activation is presumed to have high sensitivity as the signal intensity is monitored within a specific, defined area. Thus, for the extraction of brain activation patterns of micro-domains, such as BA3, monitoring the BOLD signal that reflects the nerve activation intensity more sensitively is likely to be advantageous.
Collapse
Affiliation(s)
- Mi-Hyun Choi
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - Kyu-Beom Kim
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - Ye-Jin Kim
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - Ji-Su Kim
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - Hyung-Sik Kim
- Department of Mechatronics Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - Jeong-Han Yi
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - Soon-Cheol Chung
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| |
Collapse
|
2
|
Brewer AA, Barton B. Cortical field maps across human sensory cortex. Front Comput Neurosci 2023; 17:1232005. [PMID: 38164408 PMCID: PMC10758003 DOI: 10.3389/fncom.2023.1232005] [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: 06/03/2023] [Accepted: 11/07/2023] [Indexed: 01/03/2024] Open
Abstract
Cortical processing pathways for sensory information in the mammalian brain tend to be organized into topographical representations that encode various fundamental sensory dimensions. Numerous laboratories have now shown how these representations are organized into numerous cortical field maps (CMFs) across visual and auditory cortex, with each CFM supporting a specialized computation or set of computations that underlie the associated perceptual behaviors. An individual CFM is defined by two orthogonal topographical gradients that reflect two essential aspects of feature space for that sense. Multiple adjacent CFMs are then organized across visual and auditory cortex into macrostructural patterns termed cloverleaf clusters. CFMs within cloverleaf clusters are thought to share properties such as receptive field distribution, cortical magnification, and processing specialization. Recent measurements point to the likely existence of CFMs in the other senses, as well, with topographical representations of at least one sensory dimension demonstrated in somatosensory, gustatory, and possibly olfactory cortical pathways. Here we discuss the evidence for CFM and cloverleaf cluster organization across human sensory cortex as well as approaches used to identify such organizational patterns. Knowledge of how these topographical representations are organized across cortex provides us with insight into how our conscious perceptions are created from our basic sensory inputs. In addition, studying how these representations change during development, trauma, and disease serves as an important tool for developing improvements in clinical therapies and rehabilitation for sensory deficits.
Collapse
Affiliation(s)
- Alyssa A. Brewer
- mindSPACE Laboratory, Departments of Cognitive Sciences and Language Science (by Courtesy), Center for Hearing Research, University of California, Irvine, Irvine, CA, United States
| | - Brian Barton
- mindSPACE Laboratory, Department of Cognitive Sciences, University of California, Irvine, Irvine, CA, United States
| |
Collapse
|
3
|
Cole DM, Stämpfli P, Gandia R, Schibli L, Gantner S, Schuetz P, Meier ML. In the back of your mind: Cortical mapping of paraspinal afferent inputs. Hum Brain Mapp 2022; 43:4943-4953. [PMID: 35979921 PMCID: PMC9582373 DOI: 10.1002/hbm.26052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/22/2022] [Accepted: 08/02/2022] [Indexed: 11/06/2022] Open
Abstract
Topographic organisation is a hallmark of vertebrate cortex architecture, characterised by ordered projections of the body's sensory surfaces onto brain systems. High-resolution functional magnetic resonance imaging (fMRI) has proven itself as a valuable tool to investigate the cortical landscape and its (mal-)adaptive plasticity with respect to various body part representations, in particular extremities such as the hand and fingers. Less is known, however, about the cortical representation of the human back. We therefore validated a novel, MRI-compatible method of mapping cortical representations of sensory afferents of the back, using vibrotactile stimulation at varying frequencies and paraspinal locations, in conjunction with fMRI. We expected high-frequency stimulation to be associated with differential neuronal activity in the primary somatosensory cortex (S1) compared with low-frequency stimulation and that somatosensory representations would differ across the thoracolumbar axis. We found significant differences between neural representations of high-frequency and low-frequency stimulation and between representations of thoracic and lumbar paraspinal locations, in several bilateral S1 sub-regions, and in regions of the primary motor cortex (M1). High-frequency stimulation preferentially activated Brodmann Area (BA) regions BA3a and BA4p, whereas low-frequency stimulation was more encoded in BA3b and BA4a. Moreover, we found clear topographic differences in S1 for representations of the upper and lower back during high-frequency stimulation. We present the first neurobiological validation of a method for establishing detailed cortical maps of the human back, which might serve as a novel tool to evaluate the pathological significance of neuroplastic changes in clinical conditions such as chronic low back pain.
Collapse
Affiliation(s)
- David M Cole
- Integrative Spinal Research, Department of Chiropractic Medicine, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.,Department of Psychiatry, Psychotherapy and Psychosomatics, Hospital of Psychiatry, University of Zurich, Zurich, Switzerland
| | - Philipp Stämpfli
- Department of Psychiatry, Psychotherapy and Psychosomatics, Hospital of Psychiatry, University of Zurich, Zurich, Switzerland.,MR-Center of the Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Robert Gandia
- Competence Center Thermal Energy Storage, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Louis Schibli
- Competence Center Thermal Energy Storage, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Sandro Gantner
- Competence Center Thermal Energy Storage, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Philipp Schuetz
- Competence Center Thermal Energy Storage, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Michael L Meier
- Integrative Spinal Research, Department of Chiropractic Medicine, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| |
Collapse
|
4
|
Darki F, Ferrario A, Rankin J. Hierarchical processing underpins competition in tactile perceptual bistability. J Comput Neurosci 2022; 51:343-360. [PMID: 37204542 PMCID: PMC10404575 DOI: 10.1007/s10827-023-00852-0] [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: 11/07/2022] [Revised: 04/25/2023] [Accepted: 04/28/2023] [Indexed: 05/20/2023]
Abstract
Ambiguous sensory information can lead to spontaneous alternations between perceptual states, recently shown to extend to tactile perception. The authors recently proposed a simplified form of tactile rivalry which evokes two competing percepts for a fixed difference in input amplitudes across antiphase, pulsatile stimulation of the left and right fingers. This study addresses the need for a tactile rivalry model that captures the dynamics of perceptual alternations and that incorporates the structure of the somatosensory system. The model features hierarchical processing with two stages. The first and the second stages of model could be located at the secondary somatosensory cortex (area S2), or in higher areas driven by S2. The model captures dynamical features specific to the tactile rivalry percepts and produces general characteristics of perceptual rivalry: input strength dependence of dominance times (Levelt's proposition II), short-tailed skewness of dominance time distributions and the ratio of distribution moments. The presented modelling work leads to experimentally testable predictions. The same hierarchical model could generalise to account for percept formation, competition and alternations for bistable stimuli that involve pulsatile inputs from the visual and auditory domains.
Collapse
Affiliation(s)
- Farzaneh Darki
- Department of Mathematics, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Andrea Ferrario
- Biorobotics Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - James Rankin
- Department of Mathematics, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| |
Collapse
|
5
|
Janko D, Thoenes K, Park D, Willoughby WR, Horton M, Bolding M. Somatotopic Mapping of the Fingers in the Somatosensory Cortex Using Functional Magnetic Resonance Imaging: A Review of Literature. Front Neuroanat 2022; 16:866848. [PMID: 35847829 PMCID: PMC9277538 DOI: 10.3389/fnana.2022.866848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/16/2022] [Indexed: 11/29/2022] Open
Abstract
Multiple studies have demonstrated finger somatotopy in humans and other primates using a variety of brain mapping techniques including functional magnetic resonance imaging (fMRI). Here, we review the literature to better understand the reliability of fMRI for mapping the somatosensory cortex. We have chosen to focus on the hand and fingers as these areas have the largest representation and have been the subject of the largest number of somatotopic mapping experiments. Regardless of the methods used, individual finger somatosensory maps were found to be organized across Brodmann areas (BAs) 3b, 1, and 2 in lateral-to-medial and inferior-to-superior fashion moving from the thumb to the pinky. However, some consistent discrepancies are found that depend principally on the method used to stimulate the hand and fingers. Therefore, we suggest that a comparative analysis of different types of stimulation be performed to address the differences described in this review.
Collapse
Affiliation(s)
- Daniel Janko
- Department of Psychology, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kristina Thoenes
- Edward Via College of Osteopathic Medicine Auburn, Auburn, AL, United States
| | - Dahye Park
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - W R Willoughby
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Meredith Horton
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mark Bolding
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, United States
| |
Collapse
|
6
|
Oda H, Tsujinaka R, Fukuda S, Sawaguchi Y, Hiraoka K. Tactile perception of right middle fingertip suppresses excitability of motor cortex supplying right first dorsal interosseous muscle. Neuroscience 2022; 494:82-93. [PMID: 35588919 DOI: 10.1016/j.neuroscience.2022.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/08/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022]
Abstract
The present study examined whether tactile perception of the fingertip modulates excitability of the motor cortex supplying the intrinsic hand muscle and whether this modulation is specific to the fingertip stimulated and the muscle and hand tested. Tactile stimulation was given to one of the five fingertips in the left or right hand, and transcranial magnetic stimulation eliciting motor evoked potential in the first dorsal interosseous muscle (FDI) or abductor digiti minimi was given 200 ms after the onset of tactile stimulation. The corticospinal excitability of the FDI at rest was suppressed by the tactile stimulation of the right middle fingertip, but such suppression was absent for the other fingers stimulated and for the other muscle or hand tested. The persistence and amplitude of the F-wave was not significantly influenced by tactile stimulation of the fingertip in the right hand. These findings indicate that tactile perception of the right middle fingertip suppresses excitability of the motor cortex supplying the right FDI at rest. The suppression of corticospinal excitability was absent during tonic contraction of the right FDI, indicating that the motor execution process interrupts the tactile perception-induced suppression of motor cortical excitability supplying the right FDI. These findings are in line with a view that the tactile perception of the right middle finger induces surround inhibition of the motor cortex supplying the prime mover of the finger neighboring the stimulated finger.
Collapse
Affiliation(s)
- Hitoshi Oda
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino city, Osaka, Japan
| | - Ryo Tsujinaka
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino city, Osaka, Japan
| | - Shiho Fukuda
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino city, Osaka, Japan
| | - Yasushi Sawaguchi
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino city, Osaka, Japan
| | - Koichi Hiraoka
- College of Health and Human Sciences, Osaka Prefecture University, Habikino city, Osaka, Japan.
| |
Collapse
|
7
|
Schellekens W, Thio M, Badde S, Winawer J, Ramsey N, Petridou N. A touch of hierarchy: population receptive fields reveal fingertip integration in Brodmann areas in human primary somatosensory cortex. Brain Struct Funct 2021; 226:2099-2112. [PMID: 34091731 PMCID: PMC8354965 DOI: 10.1007/s00429-021-02309-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 05/26/2021] [Indexed: 12/03/2022]
Abstract
Several neuroimaging studies have shown the somatotopy of body part representations in primary somatosensory cortex (S1), but the functional hierarchy of distinct subregions in human S1 has not been adequately addressed. The current study investigates the functional hierarchy of cyto-architectonically distinct regions, Brodmann areas BA3, BA1, and BA2, in human S1. During functional MRI experiments, we presented participants with vibrotactile stimulation of the fingertips at three different vibration frequencies. Using population Receptive Field (pRF) modeling of the fMRI BOLD activity, we identified the hand region in S1 and the somatotopy of the fingertips. For each voxel, the pRF center indicates the finger that most effectively drives the BOLD signal, and the pRF size measures the spatial somatic pooling of fingertips. We find a systematic relationship of pRF sizes from lower-order areas to higher-order areas. Specifically, we found that pRF sizes are smallest in BA3, increase slightly towards BA1, and are largest in BA2, paralleling the increase in visual receptive field size as one ascends the visual hierarchy. Additionally, we find that the time-to-peak of the hemodynamic response in BA3 is roughly 0.5 s earlier compared to BA1 and BA2, further supporting the notion of a functional hierarchy of subregions in S1. These results were obtained during stimulation of different mechanoreceptors, suggesting that different afferent fibers leading up to S1 feed into the same cortical hierarchy.
Collapse
Affiliation(s)
- W Schellekens
- Department of Radiology, Center for Image Sciences, UMC Utrecht, Q101.132, P.O.Box 85500, 3508 GA, Utrecht, The Netherlands.
| | - M Thio
- Department of Radiology, Center for Image Sciences, UMC Utrecht, Q101.132, P.O.Box 85500, 3508 GA, Utrecht, The Netherlands
| | - S Badde
- Department of Psychology and Center of Neural Science, NYU, New York, USA
| | - J Winawer
- Department of Psychology and Center of Neural Science, NYU, New York, USA
| | - N Ramsey
- Department of Neurology and Neurosurgery, UMC Utrecht, Utrecht, The Netherlands
| | - N Petridou
- Department of Radiology, Center for Image Sciences, UMC Utrecht, Q101.132, P.O.Box 85500, 3508 GA, Utrecht, The Netherlands
| |
Collapse
|
8
|
Abstract
In perceptual rivalry, ambiguous sensory information leads to dynamic changes in the perceptual interpretation of fixed stimuli. This phenomenon occurs when participants receive sensory stimuli that support two or more distinct interpretations; this results in spontaneous alternations between possible perceptual interpretations. Perceptual rivalry has been widely studied across different sensory modalities including vision, audition, and to a limited extent, in the tactile domain. Common features of perceptual rivalry across various ambiguous visual and auditory paradigms characterize the randomness of switching times and their dependence on input strength manipulations (Levelt's propositions). It is still unclear whether the general characteristics of perceptual rivalry are preserved with tactile stimuli. This study aims to introduce a simple tactile stimulus capable of generating perceptual rivalry and explores whether general features of perceptual rivalry from other modalities extend to the tactile domain. Our results confirm that Levelt's proposition II extends to tactile bistability, and that the stochastic characteristics of irregular perceptual alternations agree with non-tactile modalities. An analysis of correlations between subsequent perceptual phases reveals a significant positive correlation at lag 1 (as found in visual bistability), and a negative correlation for lag 2 (in contrast with visual bistability).
Collapse
|
9
|
Thomas J, Sharma D, Mohanta S, Jain N. Resting-State functional networks of different topographic representations in the somatosensory cortex of macaque monkeys and humans. Neuroimage 2020; 228:117694. [PMID: 33385552 DOI: 10.1016/j.neuroimage.2020.117694] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 11/16/2022] Open
Abstract
Information processing in the brain is mediated through a complex functional network architecture whose comprising nodes integrate and segregate themselves on different timescales. To gain an understanding of the network function it is imperative to identify and understand the network structure with respect to the underlying anatomical connectivity and the topographic organization. Here we show that the previously described resting-state network for the somatosensory area 3b comprises of distinct networks that are characteristic for different topographic representations. Seed-based resting-state functional connectivity analysis in macaque monkeys and humans using BOLD-fMRI signals from the face, the hand and rest of the medial somatosensory representations of area 3b revealed different correlation patterns. Both monkeys and humans have many similarities in the connectivity networks, although the networks are more complex in humans with many more nodes. In both the species face area network has the highest ipsilateral and contralateral connectivity, which included areas 3b and 4, and ventral premotor area. The area 3b hand network included ipsilateral hand representation in area 4. The emergent functional network structures largely reflect the known anatomical connectivity. Our results show that different body part representations in area 3b have independent functional networks perhaps reflecting differences in the behavioral use of different body parts. The results also show that large cortical areas if considered together, do not give a complete and accurate picture of the network architecture.
Collapse
Affiliation(s)
- John Thomas
- National Brain Research Centre, NH 8, Manesar 122052, Haryana, India
| | - Dixit Sharma
- National Brain Research Centre, NH 8, Manesar 122052, Haryana, India
| | - Sounak Mohanta
- National Brain Research Centre, NH 8, Manesar 122052, Haryana, India
| | - Neeraj Jain
- National Brain Research Centre, NH 8, Manesar 122052, Haryana, India.
| |
Collapse
|
10
|
Kuehn E, Pleger B. Encoding schemes in somatosensation: From micro- to meta-topography. Neuroimage 2020; 223:117255. [PMID: 32800990 DOI: 10.1016/j.neuroimage.2020.117255] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 07/15/2020] [Accepted: 08/07/2020] [Indexed: 12/23/2022] Open
Abstract
Encoding schemes are systematic large-scale arrangements that convert incoming sensory information into a format required for further information processing. The increased spatial resolution of brain images obtained with ultra-high field magnetic resonance imaging at 7 T (7T-MRI) and above increases the granularity and precision of processing units that mediate the link between neuronal encoding and functional readouts. Here, these new developments are reviewed with a focus on human tactile encoding schemes derived from small-scale processing units (in the order of 0.5-5 mm) that are relevant for theoretical and practical concepts of somatosensory encoding and cortical plasticity. Precisely, we review recent approaches to characterize meso-scale maps, layer units, and cortical fields in the sensorimotor cortex of the living human brain and discuss their impact on theories of perception, motor control, topographic encoding, and cortical plasticity. Finally, we discuss concepts on the integration of small-scale processing units into functional networks that span multiple topographic maps and multiple cortical areas. Novel research areas are highlighted that may help to bridge the gap between cortical microstructure and meta-topographic models on brain anatomy and function.
Collapse
Affiliation(s)
- Esther Kuehn
- Institute for Cognitive Neurology and Dementia Research (IKND), Otto-von-Guericke University Magdeburg, 39120, Germany; Center for Behavioral Brain Sciences (CBBS) Magdeburg, Magdeburg 39120, Germany.
| | - Burkhard Pleger
- Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum 44789, Germany
| |
Collapse
|
11
|
Bahia CP, Vianna-Barbosa RJ, Tovar-Moll F, Lent R. Terminal Arbors of Callosal Axons Undergo Plastic Changes in Early-Amputated Rats. Cereb Cortex 2020; 29:1460-1472. [PMID: 30873555 DOI: 10.1093/cercor/bhy043] [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: 10/10/2017] [Revised: 02/04/2018] [Accepted: 02/07/2018] [Indexed: 12/26/2022] Open
Abstract
Sensory information is processed in specific brain regions, and shared between the cerebral hemispheres by axons that cross the midline through the corpus callosum. However, sensory deprivation usually causes sensory losses and/or functional changes. This is the case of people who suffered limb amputation and show changes of body map organization within the somatosensory cortex (S1) of the deafferented cerebral hemisphere (contralateral to the amputated limb), as well as in the afferented hemisphere (ipsilateral to the amputated limb). Although several studies have approached these functional changes, the possible finer morphological alterations, such as those occurring in callosal axons, still remain unknown. The present work combined histochemistry, single-axon tracing and 3D microscopy to analyze the fine morphological changes that occur in callosal axons of the forepaw representation in early amputated rats. We showed that the forepaw representation in S1 was reduced in the deafferented hemisphere and expanded in the afferented side. Accordingly, after amputation, callosal axons originating from the deafferented cortex undergo an expansion of their terminal arbors with increased number of terminal boutons within the homotopic representation at the afferented cerebral hemisphere. Similar microscale structural changes may underpin the macroscale morphological and functional phenomena that characterize limb amputation in humans.
Collapse
Affiliation(s)
- Carlomagno Pacheco Bahia
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, CEP 21941-902 Rio de Janeiro (RJ), Brazil.,Institute of Health Sciences, Federal University of Pará, CEP 66075-110 Belém (PA), Brazil
| | - Rodrigo Jorge Vianna-Barbosa
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, CEP 21941-902 Rio de Janeiro (RJ), Brazil
| | - Fernanda Tovar-Moll
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, CEP 21941-902 Rio de Janeiro (RJ), Brazil.,D'Or Institute of Research and Education, CEP 22281-100 Rio de Janeiro (RJ), Brazil
| | - Roberto Lent
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, CEP 21941-902 Rio de Janeiro (RJ), Brazil
| |
Collapse
|
12
|
Bayesian population receptive field modeling in human somatosensory cortex. Neuroimage 2020; 208:116465. [DOI: 10.1016/j.neuroimage.2019.116465] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 11/17/2022] Open
|
13
|
Wahlbom A, Enander JMD, Bengtsson F, Jörntell H. Focal neocortical lesions impair distant neuronal information processing. J Physiol 2019; 597:4357-4371. [PMID: 31342538 PMCID: PMC6852703 DOI: 10.1113/jp277717] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Parts of the fields of neuroscience and neurology consider the neocortex to be a functionally parcelled structure. Viewed through such a conceptual filter, there are multiple clinical observations after localized stroke lesions that seem paradoxical. We tested the effect that localized stroke-like lesions have on neuronal information processing in a part of the neocortex that is distant to the lesion using animal experiments. We find that the distant lesion degrades the quality of neuronal information processing of tactile input patterns in primary somatosensory cortex. The findings suggest that even the processing of primary sensory information depends on an intact neocortical network, with the implication that all neocortical processing may rely on widespread interactions across large parts of the cortex. ABSTRACT Recent clinical studies report a surprisingly weak relationship between the location of cortical brain lesions and the resulting functional deficits. From a neuroscience point of view, such findings raise questions as to what extent functional localization applies in the neocortex and to what extent the functions of different regions depend on the integrity of others. Here we provide an in-depth analysis of the changes in the function of the neocortical neuronal networks after distant focal stroke-like lesions in the anaesthetized rat. Using a recently introduced high resolution analysis of neuronal information processing, consisting of pre-set spatiotemporal patterns of tactile afferent activation against which the neuronal decoding performance can be quantified, we found that stroke-like lesions in distant parts of the cortex significantly degraded the decoding performance of individual neocortical neurons in the primary somatosensory cortex (decoding performance decreased from 30.9% to 24.2% for n = 22 neurons, Wilcoxon signed rank test, P = 0.028). This degrading effect was not due to changes in the firing frequency of the neuron (Wilcoxon signed rank test, P = 0.499) and was stronger the higher the decoding performance of the neuron, indicating a specific impact on the information processing capacity in the cortex. These findings suggest that even primary sensory processing depends on widely distributed cortical networks and could explain observations of focal stroke lesions affecting a large range of functions.
Collapse
Affiliation(s)
- Anders Wahlbom
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, BMC F10 Tornavägen 10, SE-221 84, Lund, Sweden
| | - Jonas M D Enander
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, BMC F10 Tornavägen 10, SE-221 84, Lund, Sweden
| | - Fredrik Bengtsson
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, BMC F10 Tornavägen 10, SE-221 84, Lund, Sweden
| | - Henrik Jörntell
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, BMC F10 Tornavägen 10, SE-221 84, Lund, Sweden
| |
Collapse
|
14
|
Enander JMD, Spanne A, Mazzoni A, Bengtsson F, Oddo CM, Jörntell H. Ubiquitous Neocortical Decoding of Tactile Input Patterns. Front Cell Neurosci 2019; 13:140. [PMID: 31031596 PMCID: PMC6474209 DOI: 10.3389/fncel.2019.00140] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 03/20/2019] [Indexed: 11/13/2022] Open
Abstract
Whereas functional localization historically has been a key concept in neuroscience, direct neuronal recordings show that input of a particular modality can be recorded well outside its primary receiving areas in the neocortex. Here, we wanted to explore if such spatially unbounded inputs potentially contain any information about the quality of the input received. We utilized a recently introduced approach to study the neuronal decoding capacity at a high resolution by delivering a set of electrical, highly reproducible spatiotemporal tactile afferent activation patterns to the skin of the contralateral second digit of the forepaw of the anesthetized rat. Surprisingly, we found that neurons in all areas recorded from, across all cortical depths tested, could decode the tactile input patterns, including neurons of the primary visual cortex. Within both somatosensory and visual cortical areas, the combined decoding accuracy of a population of neurons was higher than for the best performing single neuron within the respective area. Such cooperative decoding indicates that not only did individual neurons decode the input, they also did so by generating responses with different temporal profiles compared to other neurons, which suggests that each neuron could have unique contributions to the tactile information processing. These findings suggest that tactile processing in principle could be globally distributed in the neocortex, possibly for comparison with internal expectations and disambiguation processes relying on other modalities.
Collapse
Affiliation(s)
- Jonas M D Enander
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Anton Spanne
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Alberto Mazzoni
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Fredrik Bengtsson
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | - Henrik Jörntell
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, Lund, Sweden
| |
Collapse
|
15
|
Lamp G, Goodin P, Palmer S, Low E, Barutchu A, Carey LM. Activation of Bilateral Secondary Somatosensory Cortex With Right Hand Touch Stimulation: A Meta-Analysis of Functional Neuroimaging Studies. Front Neurol 2019; 9:1129. [PMID: 30687211 PMCID: PMC6335946 DOI: 10.3389/fneur.2018.01129] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 12/10/2018] [Indexed: 12/30/2022] Open
Abstract
Background: Brain regions involved in processing somatosensory information have been well documented through lesion, post-mortem, animal, and more recently, structural and functional neuroimaging studies. Functional neuroimaging studies characterize brain activation related to somatosensory processing; yet a meta-analysis synthesis of these findings is currently lacking and in-depth knowledge of the regions involved in somatosensory-related tasks may also be confounded by motor influences. Objectives: Our Activation Likelihood Estimate (ALE) meta-analysis sought to quantify brain regions that are involved in the tactile processing of the right (RH) and left hands (LH) separately, with the exclusion of motor related activity. Methods: The majority of studies (n = 41) measured activation associated with RH tactile stimulation. RH activation studies were grouped into those which conducted whole-brain analyses (n = 29) and those which examined specific regions of interest (ROI; n = 12). Few studies examined LH activation, though all were whole-brain studies (N = 7). Results: Meta-analysis of brain activation associated with RH tactile stimulation (whole-brain studies) revealed large clusters of activation in the left primary somatosensory cortex (S1) and bilaterally in the secondary somatosensory cortex (S2; including parietal operculum) and supramarginal gyrus (SMG), as well as the left anterior cingulate. Comparison between findings from RH whole-brain and ROI studies revealed activation as expected, but restricted primarily to S1 and S2 regions. Further, preliminary analyses of LH stimulation studies only, revealed two small clusters within the right S1 and S2 regions, likely limited due to the small number of studies. Contrast analyses revealed the one area of overlap for RH and LH, was right secondary somatosensory region. Conclusions: Findings from the whole-brain meta-analysis of right hand tactile stimulation emphasize the importance of taking into consideration bilateral activation, particularly in secondary somatosensory cortex. Further, the right parietal operculum/S2 region was commonly activated for right and left hand tactile stimulation, suggesting a lateralized pattern of somatosensory activation in right secondary somatosensory region. Implications for further research and for possible differences in right and left hemispheric stroke lesions are discussed.
Collapse
Affiliation(s)
- Gemma Lamp
- Neurorehabilitation and Recovery, Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, VIC, Australia
- Occupational Therapy, School of Allied Health, La Trobe University, Bundoora, VIC, Australia
| | - Peter Goodin
- Neurorehabilitation and Recovery, Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, VIC, Australia
| | - Susan Palmer
- Neurorehabilitation and Recovery, Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, VIC, Australia
| | - Essie Low
- Neurorehabilitation and Recovery, Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, VIC, Australia
- Department of Neurology, Sunshine Hospital, Western Health, Melbourne, VIC, Australia
- Department of Psychology, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Ayla Barutchu
- Neurorehabilitation and Recovery, Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, VIC, Australia
- Balliol College, University of Oxford, Oxford, United Kingdom
| | - Leeanne M. Carey
- Neurorehabilitation and Recovery, Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, VIC, Australia
- Occupational Therapy, School of Allied Health, La Trobe University, Bundoora, VIC, Australia
| |
Collapse
|
16
|
Hage B, Way E, Barlow SM, Bashford GR. Real-Time Cerebral Hemodynamic Response to Tactile Somatosensory Stimulation. J Neuroimaging 2018; 28:615-620. [PMID: 29992676 PMCID: PMC6212317 DOI: 10.1111/jon.12546] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/25/2018] [Accepted: 06/25/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Recent studies in rodents suggest that somatosensory stimulation could provide neuroprotection during ischemic stroke by inducing plasticity in the cortex-vasculature relationship. While functional magnetic resonance imaging (fMRI) has shown that somatosensory stimulation increases cerebral blood flow (CBF) over several seconds, subsecond changes in CBF in the basal cerebral arteries have rarely been studied due to temporal resolution limitations. This study characterized hemodynamic changes in the middle cerebral arteries (MCAs) during somatosensory stimulation with high temporal resolution (100 samples/s) using functional transcranial Doppler ultrasound (fTCD). METHODS Pneumotactile somatosensory stimulation, consisting of punctate pressure pulses traversing the glabrous skin of the hand at 25 cm/s, was used to induce CBF velocity (CBFV) response curves. Changes in CBFV were measured in the bilateral MCAs using fTCD. All 12 subjects underwent three consecutive trials consisting of 20 seconds of stimulation followed by 5 minutes of rest. RESULTS Sharp, bilateral increases in CBFV of about 20% (left MCA = 20.5%, right MCA = 18.8%) and sharp decreases in pulsatility index of about 8% were observed during stimulation. Left lateralization of up to 3.9% was also observed. The magnitude of the initial increase in CBFV showed significant adaptation between subsequent trials. CONCLUSIONS Pneumotactile somatosensory stimulation is a potent stimulus that can evoke large, rapid hemodynamic changes, with adaptation between successive stimulus applications. Due to its high temporal resolution, fTCD is useful for identifying quickly evolving hemodynamic responses, and for correlating changes in hemodynamic parameters such as pulsatility index (PI) and CBFV.
Collapse
Affiliation(s)
- Benjamin Hage
- Department of Biological Systems Engineering, University of Nebraska-Lincoln
| | - Emily Way
- Department of Biological Systems Engineering, University of Nebraska-Lincoln
| | - Steven M. Barlow
- Department of Biological Systems Engineering, University of Nebraska-Lincoln
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln
| | - Gregory R. Bashford
- Department of Biological Systems Engineering, University of Nebraska-Lincoln
| |
Collapse
|
17
|
Gallo S, Paracampo R, Müller-Pinzler L, Severo MC, Blömer L, Fernandes-Henriques C, Henschel A, Lammes BK, Maskaljunas T, Suttrup J, Avenanti A, Keysers C, Gazzola V. The causal role of the somatosensory cortex in prosocial behaviour. eLife 2018; 7:32740. [PMID: 29735015 PMCID: PMC5973831 DOI: 10.7554/elife.32740] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 04/20/2018] [Indexed: 01/09/2023] Open
Abstract
Witnessing another person’s suffering elicits vicarious brain activity in areas that are active when we ourselves are in pain. Whether this activity influences prosocial behavior remains the subject of debate. Here participants witnessed a confederate express pain through a reaction of the swatted hand or through a facial expression, and could decide to reduce that pain by donating money. Participants donate more money on trials in which the confederate expressed more pain. Electroencephalography shows that activity of the somatosensory cortex I (SI) hand region explains variance in donation. Transcranial magnetic stimulation (TMS) shows that altering this activity interferes with the pain–donation coupling only when pain is expressed by the hand. High-definition transcranial direct current stimulation (HD-tDCS) shows that altering SI activity also interferes with pain perception. These experiments show that vicarious somatosensory activations contribute to prosocial decision-making and suggest that they do so by helping to transform observed reactions of affected body-parts into accurate perceptions of pain that are necessary for decision-making. When we experience physical pain, certain areas in our brain that process bodily sensation and emotions switch on. If we see someone else in pain, many of the same regions also get activated. In contrast, convicted criminals with psychopathic traits have less activation in these areas of the brain when witnessing someone’s pain; they also show less empathy and disregard the needs of others. This suggests that a lack of this ‘shared activations’ may lead to problems in empathy. In fact, many scientists believe that shared activations are why we feel empathy for people in pain, and why we are driven to help them. Yet, there is little direct evidence about how the activity in the pain processing parts of the brain actually influences helpful behavior. As a result, some scientists now argue that empathy-related processes may actually contribute very little to helping behavior. Gallo et al. designed an experiment where participants watched videos of someone having their hand swatted with a belt, and showing different levels of pain as a result. The volunteers could decide to reduce the amount of pain the person received by donating money they could have taken home. The more pain the participants thought the victim was in, the more money they gave up to lessen it. During the study, the activity in the brain region that processes pain in the hand was also measured in the participants. The more active this region was, the more money people donated to help. Then, Gallo et al. used techniques that interfered with the activity of the brain area involved in perceiving sensations from the hand. This interference changed how accurately participants assessed the victim's pain. It also disrupted the link between donations and the victim's perceived pain: the amount of money people gave no longer matched the level of pain they had witnessed. This suggests that the brain areas that perceive sensations of pain in the self, which evolved primarily to experience our own sensations, also have a social function. They transform the sight of bodily harm into an accurate feeling for how much pain the victim experiences. The findings also show that we need this feeling so we can adapt our help to the needs of others. In the current debate about the role of empathy in helping behaviors, this study demonstrates that empathy-related brain activity indeed promotes helping by allowing us to detect those that need our assistance. Understanding the relationship between helping behavior and the activity of the brain may further lead to treatments for individuals with antisocial behavior and for children with callous and unemotional traits, a disorder that is associated with a lack of empathy and a general disregard for others.
Collapse
Affiliation(s)
- Selene Gallo
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Riccardo Paracampo
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands.,Department of Psychology, Center for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, Italy.,IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Laura Müller-Pinzler
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands.,Department of Psychiatry and Psychotherapy, Social Neuroscience Lab, University of Lübeck, Lübeck, Germany
| | - Mario Carlo Severo
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Laila Blömer
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Carolina Fernandes-Henriques
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Anna Henschel
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Balint Kalista Lammes
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Tatjana Maskaljunas
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Judith Suttrup
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands
| | - Alessio Avenanti
- Department of Psychology, Center for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, Italy.,IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Christian Keysers
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands.,Faculty of Social and Behavioural Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Valeria Gazzola
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Art and Sciences (KNAW), Amsterdam, Netherlands.,Faculty of Social and Behavioural Sciences, University of Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
18
|
Shen G, Smyk NJ, Meltzoff AN, Marshall PJ. Using somatosensory mismatch responses as a window into somatotopic processing of tactile stimulation. Psychophysiology 2017; 55:e13030. [PMID: 29139557 DOI: 10.1111/psyp.13030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 11/30/2022]
Abstract
Brain responses to tactile stimulation have often been studied through the examination of ERPs elicited to touch on the body surface. Here, we examined two factors potentially modulating the amplitude of the somatosensory mismatch negativity (sMMN) and P300 responses elicited by touch to pairs of body parts: (a) the distance between the representation of these body parts in somatosensory cortex, and (b) the physical distances between the stimulated points on the body surface. The sMMN and the P300 response were elicited by tactile stimulation in two oddball protocols. One protocol leveraged a discontinuity in cortical somatotopic organization, and involved stimulation of either the neck or the hand in relation to stimulation of the lip. The other protocol involved stimulation to the third or fifth finger in relation to the second finger. The neck-lip pairing resulted in significantly larger sMMN responses (with shorter latencies) than the hand-lip pairing, whereas the reverse was true for the amplitude of the P300. Mean sMMN amplitude and latency did not differ between finger pairings. However, larger P300 responses were elicited to stimulation of the fifth finger than the third finger. These results suggest that, for certain combinations of body parts, early automatic somatosensory mismatch responses may be influenced by distance between the cortical representations of these body parts, whereas the later P300 response may be more influenced by the distance between stimulated body parts on the body surface. Future investigations can shed more light on this novel suggestion.
Collapse
Affiliation(s)
- Guannan Shen
- Department of Psychology, Temple University, Philadelphia, Pennsylvania, USA
| | - Nathan J Smyk
- Department of Psychology, Temple University, Philadelphia, Pennsylvania, USA
| | - Andrew N Meltzoff
- Institute for Learning and Brain Sciences, University of Washington, Seattle, Washington, USA
| | - Peter J Marshall
- Department of Psychology, Temple University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
19
|
Papadelis C, Butler EE, Rubenstein M, Sun L, Zollei L, Nimec D, Snyder B, Grant PE. Reorganization of the somatosensory cortex in hemiplegic cerebral palsy associated with impaired sensory tracts. Neuroimage Clin 2017; 17:198-212. [PMID: 29159037 PMCID: PMC5683344 DOI: 10.1016/j.nicl.2017.10.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/27/2017] [Accepted: 10/18/2017] [Indexed: 02/08/2023]
Abstract
Functional neuroimaging studies argue that sensory deficits in hemiplegic cerebral palsy (HCP) are related to deviant somatosensory processing in the ipsilesional primary somatosensory cortex (S1). A separate body of structural neuroimaging literature argues that these deficits are due to structural damage of the ascending sensory tracts (AST). The relationship between the functional and structural integrity of the somatosensory system and the sensory performance is largely unknown in HCP. To address this relationship, we combined findings from magnetoencephalography (MEG) and probabilistic diffusion tractography (PDT) in 10 children with HCP and 13 typically developing (TD) children. With MEG, we mapped the functionally active regions in the contralateral S1 during tactile stimulation of the thumb, middle, and little fingers of both hands. Using these MEG-defined functional active regions as regions of interest for PDT, we estimated the diffusion parameters of the AST. Somatosensory function was assessed via two-point discrimination tests. Our MEG data showed: (i) an abnormal somatotopic organization in all children with HCP in either one or both of their hemispheres; (ii) longer Euclidean distances between the digit maps in the S1 of children with HCP compared to TD children; (iii) suppressed gamma responses at early latencies for both hemispheres of children with HCP; and (iv) a positive correlation between the Euclidean distances and the sensory tests for the more affected hemisphere of children with HCP. Our MEG-guided PDT data showed: (i) higher mean and radian diffusivity of the AST in children with HCP; (ii) a positive correlation between the axial diffusivity of the AST with the sensory tests for the more affected hemisphere; and (iii) a negative correlation between the gamma power change and the AD of the AST for the MA hemisphere. Our findings associate for the first time bilateral cortical functional reorganization in the S1 of HCP children with abnormalities in the structural integrity of the AST, and correlate these abnormalities with behaviorally-assessed sensory deficits.
Collapse
Affiliation(s)
- Christos Papadelis
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Erin E Butler
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA; William H. Neukom Institute for Computational Science, Dartmouth College, Hanover, NH, USA
| | - Madelyn Rubenstein
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Limin Sun
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Lilla Zollei
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Donna Nimec
- Department of Orthopedic Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Brian Snyder
- Department of Orthopedic Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Patricia Ellen Grant
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
20
|
Anatomical and functional properties of the foot and leg representation in areas 3b, 1 and 2 of primary somatosensory cortex in humans: A 7T fMRI study. Neuroimage 2017. [DOI: 10.1016/j.neuroimage.2017.06.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
|
21
|
Puckett AM, Bollmann S, Barth M, Cunnington R. Measuring the effects of attention to individual fingertips in somatosensory cortex using ultra-high field (7T) fMRI. Neuroimage 2017; 161:179-187. [PMID: 28801252 DOI: 10.1016/j.neuroimage.2017.08.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 06/13/2017] [Accepted: 08/03/2017] [Indexed: 11/19/2022] Open
Abstract
Attention to sensory information has been shown to modulate the neuronal processing of that information. For example, visuospatial attention acts by modulating responses at retinotopically appropriate regions of visual cortex (Puckett and DeYoe, 2015; Tootell et al. 1998). Much less, however, is known about the neuronal processing associated with attending to other modalities of sensory information. One reason for this is that visual cortex is relatively large, and therefore easier to access non-invasively in humans using tools such as functional magnetic resonance imaging (fMRI). With high-resolution fMRI, however, it is now possible to access smaller cortical areas such as primary somatosensory cortex (Martuzzi et al., 2014; Sanchez-Panchuelo et al., 2010; Schweisfurth et al. 2014; Schweizer et al. 2008). Here, we combined a novel experimental design and high-resolution fMRI at ultra-high field (7T) to measure the effects of attention to tactile stimulation in primary somatosensory cortex, S1. We find that attention modulates somatotopically appropriate regions of S1, and importantly, that this modulation can be measured at the level of the cortical representation of individual fingertips.
Collapse
Affiliation(s)
- Alexander M Puckett
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Saskia Bollmann
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Markus Barth
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ross Cunnington
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia; School of Psychology, The University of Queensland, Brisbane, QLD 4072, Australia
| |
Collapse
|
22
|
Hedrich T, Pellegrino G, Kobayashi E, Lina JM, Grova C. Comparison of the spatial resolution of source imaging techniques in high-density EEG and MEG. Neuroimage 2017; 157:531-544. [PMID: 28619655 DOI: 10.1016/j.neuroimage.2017.06.022] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/29/2017] [Accepted: 06/09/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The present study aims at evaluating and comparing electrical and magnetic distributed source imaging methods applied to high-density Electroencephalography (hdEEG) and Magnetoencephalography (MEG) data. We used resolution matrices to characterize spatial resolution properties of Minimum Norm Estimate (MNE), dynamic Statistical Parametric Mapping (dSPM), standardized Low-Resolution Electromagnetic Tomography (sLORETA) and coherent Maximum Entropy on the Mean (cMEM, an entropy-based technique). The resolution matrix provides information of the Point Spread Functions (PSF) and of the Crosstalk functions (CT), this latter being also called source leakage, as it reflects the influence of a source on its neighbors. METHODS The spatial resolution of the inverse operators was first evaluated theoretically and then with real data acquired using electrical median nerve stimulation on five healthy participants. We evaluated the Dipole Localization Error (DLE) and the Spatial Dispersion (SD) of each PSF and CT map. RESULTS cMEM showed the smallest spatial spread (SD) for both PSF and CT maps, whereas localization errors (DLE) were similar for all methods. Whereas cMEM SD values were lower in MEG compared to hdEEG, the other methods slightly favored hdEEG over MEG. In real data, cMEM provided similar localization error and significantly less spatial spread than other methods for both MEG and hdEEG. Whereas both MEG and hdEEG provided very accurate localizations, all the source imaging methods actually performed better in MEG compared to hdEEG according to all evaluation metrics, probably due to the higher signal-to-noise ratio of the data in MEG. CONCLUSION Our overall results show that all investigated methods provide similar localization errors, suggesting very accurate localization for both MEG and hdEEG when similar number of sensors are considered for both modalities. Intrinsic properties of source imaging methods as well as their behavior for well-controlled tasks, suggest an overall better performance of cMEM in regards to spatial resolution and spatial leakage for both hdEEG and MEG. This indicates that cMEM would be a good candidate for studying source localization of focal and extended generators as well as functional connectivity studies.
Collapse
Affiliation(s)
- T Hedrich
- Multimodal Functional Imaging Lab, Biomedical Engineering Dpt., McGill University, Montreal, Canada.
| | - G Pellegrino
- Multimodal Functional Imaging Lab, Biomedical Engineering Dpt., McGill University, Montreal, Canada; Neurology and Neurosurgery Department, Montreal Neurological Institute (MNI), McGill University, Montreal, Canada; San Camillo Hospital IRCCS, Venice, Italy
| | - E Kobayashi
- Neurology and Neurosurgery Department, Montreal Neurological Institute (MNI), McGill University, Montreal, Canada
| | - J M Lina
- Département de Génie Électrique, École de Technologie Supérieure, Canada; Centre de recherches mathémathiques, Université de Montréal, Montreal, Canada; Center for Advanced Research on Sleep Medecine (CEAMS), hôpital du Sacré-Coeur, Montreal, Canada
| | - C Grova
- Multimodal Functional Imaging Lab, Biomedical Engineering Dpt., McGill University, Montreal, Canada; Neurology and Neurosurgery Department, Montreal Neurological Institute (MNI), McGill University, Montreal, Canada; Physics Dpt., PERFORM Centre, Concordia University, Canada; Centre de recherches mathémathiques, Université de Montréal, Montreal, Canada
| |
Collapse
|
23
|
Effects of transcranial direct current stimulation on temperature and pain perception. Sci Rep 2017; 7:2946. [PMID: 28592857 PMCID: PMC5462761 DOI: 10.1038/s41598-017-03173-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/24/2017] [Indexed: 11/22/2022] Open
Abstract
Transcranial direct current stimulation modifies cortical excitability and in consequence some cerebral functions. In the present study we aimed to elucidate whether tDCS could affect temperature and pain perceptions in healthy subjects testing different stimulation parameters. A total of 20 healthy subjects were studied by means of quantitative sensory testing. Two different experiments were performed. First, we studied the effects of 15 minutes 2 mA anodal transcranial direct current stimulation applied over left M1 and parietal cortex in two separated sessions. Then, we tested the effects of 5 minutes tDCS over M1 by means of a sham controlled design to optimize the possibility to study minimal effects of tDCS using different polarities (cathodal and anodal) and intensities (1 and 2 mA). 2 mA anodal tDCS, when applied for both 15 and 5 minutes over the motor cortex, increased cold perception threshold. Conversely, motor cortex cathodal tDCS modulated cold perception threshold only when 1 mA intensity was used. M1-tDCS can modify the temperature perception; these effects are polarity and intensity dependent. As stimulation intensity seems critical to determine the effects, we suggest that for clinical application strong anodal tDCS (>1 mA) or weak cathodal tDCS (<2 mA) should be used for pain control.
Collapse
|
24
|
Prueckl R, Kapeller C, Kamada K, Takeuchi F, Ogawa H, Scharinger J, Guger C. Distinction of individual finger responses in somatosensory cortex using ECoG high-gamma activation mapping. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:5760-3. [PMID: 26737601 DOI: 10.1109/embc.2015.7319701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This study demonstrates the feasibility of high-gamma activity mapping for localization of somatosensory finger areas in the human brain. Identification of functional brain regions is important in surgical planning, such as for resections of epileptic foci or brain tumors. The mapping procedure is done using electrocorticography (ECoG), an invasive technique in which electrical brain signals are acquired from the cortical surface. Two epilepsy patients with implanted electrode grids participated in the study. Data were collected during a vibrotactile finger stimulation paradigm and showed significant cortical activation (p <; 0.001) in the high-gamma range over the contralateral somatosensory cortex. The results are consistent with previous studies that used fMRI in test subjects without implanted electrodes. Therefore, the results suggest that localizing the cortical representations of the fingers in clinical practice using ECoG is feasible, even without the patient's active participation.
Collapse
|
25
|
Wahnoun R, Benson M, Helms-Tillery S, Adelson PD. Delineation of somatosensory finger areas using vibrotactile stimulation, an ECoG study. Brain Behav 2015; 5:e00369. [PMID: 26516605 PMCID: PMC4614049 DOI: 10.1002/brb3.369] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/15/2015] [Accepted: 06/21/2015] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND In surgical planning for epileptic focus resection, functional mapping of eloquent cortex is attained through direct electrical stimulation of the brain. This procedure is uncomfortable, can trigger seizures or nausea, and relies on subjective evaluation. We hypothesize that a method combining vibrotactile stimulation and statistical clustering may provide improved somatosensory mapping. METHODS Seven pediatric candidates for surgical resection underwent a task in which their fingers were independently stimulated using a custom designed finger pad, during electrocorticographic monitoring. A cluster-based statistical analysis was then performed to localize the elicited activity on the recording grids. RESULTS Mid-Gamma clusters (65-115 Hz) arose in areas consistent with anatomical predictions as well as clinical findings, with five subjects presenting a somatotopic organization of the fingers. This process allowed us to delineate finger representation even in patients who were sleeping, with strong interictal activity, or when electrical stimulation did not successfully locate eloquent areas. CONCLUSIONS We suggest that this scheme, relying on the endogenous neural response rather than exogenous electrical activation, could eventually be extended to map other sensory areas and provide a faster and more objective map to better anticipate outcomes of surgical resection.
Collapse
Affiliation(s)
- Rémy Wahnoun
- Barrow Neurological Institute at Phoenix Children's Hospital Children's Neuroscience Research Phoenix Arizona ; School of Biological and Health Systems Engineering Arizona State University Tempe Arizona
| | - Michelle Benson
- Barrow Neurological Institute at Phoenix Children's Hospital Children's Neuroscience Research Phoenix Arizona
| | - Stephen Helms-Tillery
- School of Biological and Health Systems Engineering Arizona State University Tempe Arizona
| | - P David Adelson
- Barrow Neurological Institute at Phoenix Children's Hospital Children's Neuroscience Research Phoenix Arizona ; School of Biological and Health Systems Engineering Arizona State University Tempe Arizona
| |
Collapse
|
26
|
Hänselmann S, Schneiders M, Weidner N, Rupp R. Transcranial magnetic stimulation for individual identification of the best electrode position for a motor imagery-based brain-computer interface. J Neuroeng Rehabil 2015; 12:71. [PMID: 26303933 PMCID: PMC4547425 DOI: 10.1186/s12984-015-0063-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/18/2015] [Indexed: 11/18/2022] Open
Abstract
Background For the translation of noninvasive motor imagery (MI)-based brain-computer interfaces (BCIs) from the lab environment to end users at their homes, their handling must be improved. As a key component, the number of electroencephalogram (EEG)-recording electrodes has to be kept at a minimum. However, due to inter-individual anatomical and physiological variations, reducing the number of electrodes bares the risk of electrode misplacement, which will directly translate into a limited BCI performance of end users. The aim of the study is to evaluate the use of focal transcranial magnetic stimulation (TMS) as an easy tool to individually optimize electrode positioning for a MI-based BCI. For this, the area of MI-induced mu-rhythm modulation was compared with the motor hand representation area in respect to their localization and to the control performance of a MI-based BCI. Methods Focal TMS was applied to map the motor hand areas and a 48-channel high-resolution EEG was used to localize MI-induced mu-rhythm modulations in 11 able-bodied, right-handed subjects (5 male, age: 23–31). The online BCI performances of the study participants were assessed with a single next-neighbor Laplace channel consecutively placed over the motor hand area and over the area of the strongest mu-modulation. Results For most subjects, a consistent deviation between the position of the mu-modulation center and the corresponding motor hand areas well above the localization error could be observed in mediolateral and to a lesser degree in anterior-posterior direction. On an individual level, the MI-induced mu-rhythm modulation was at average found 1.6 cm (standard deviation (SD) = 1.30 cm) lateral and 0.31 cm anterior (SD = 1.39 cm) to the motor hand area and enabled a significantly better online BCI performance than the motor hand areas. Conclusion On an individual level a trend towards a consistent average spatial distance between motor hand area and mu-rhythm modulation center was found indicating that TMS may be used as a simple tool for quick individual optimization of EEG-recording electrode positions of MI-based BCIs. The study results indicate that motor hand areas of the primary motor cortex determined by TMS are not the main generators of the cortical mu-rhythm.
Collapse
Affiliation(s)
- Siegfried Hänselmann
- Heidelberg University Hospital, Spinal Cord Injury Center, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
| | - Matthias Schneiders
- Heidelberg University Hospital, Spinal Cord Injury Center, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
| | - Norbert Weidner
- Heidelberg University Hospital, Spinal Cord Injury Center, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
| | - Rüdiger Rupp
- Heidelberg University Hospital, Spinal Cord Injury Center, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
| |
Collapse
|
27
|
Sel A, Calvo-Merino B, Tuettenberg S, Forster B. When you smile, the world smiles at you: ERP evidence for self-expression effects on face processing. Soc Cogn Affect Neurosci 2015; 10:1316-22. [PMID: 25717074 DOI: 10.1093/scan/nsv009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 02/09/2015] [Indexed: 11/12/2022] Open
Abstract
Current models of emotion simulation propose that intentionally posing a facial expression can change one's subjective feelings, which in turn influences the processing of visual input. However, the underlying neural mechanism whereby one's facial emotion modulates the visual cortical responses to other's facial expressions remains unknown. To understand how one's facial expression affects visual processing, we measured participants' visual evoked potentials (VEPs) during a facial emotion judgment task of positive and neutral faces. To control for the effects of facial muscles on VEPs, we asked participants to smile (adopting an expression of happiness), to purse their lips (incompatible with smiling) or to pose with a neutral face, in separate blocks. Results showed that the smiling expression modulates face-specific visual processing components (N170/vertex positive potential) to watching other facial expressions. Specifically, when making a happy expression, neutral faces are processed similarly to happy faces. When making a neutral expression or pursing the lips, however, responses to neutral and happy face are significantly different. This effect was source localized within multisensory associative areas, angular gyrus, associative visual cortex and somatosensory cortex. We provide novel evidence that one's own emotional expression acts as a top-down influence modulating low-level neural encoding during facial perception.
Collapse
Affiliation(s)
- Alejandra Sel
- Laboratory of Action and Body, Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK, Department of Psychology, City University London, London EC1V 0HB, UK, and
| | - Beatriz Calvo-Merino
- Department of Psychology, City University London, London EC1V 0HB, UK, and Department of Psychology, Complutense University of Madrid, Madrid 28223, Spain
| | - Simone Tuettenberg
- Department of Psychology, City University London, London EC1V 0HB, UK, and
| | - Bettina Forster
- Department of Psychology, City University London, London EC1V 0HB, UK, and
| |
Collapse
|
28
|
Yao J, Chen A, Kuiken T, Carmona C, Dewald J. Sensory cortical re-mapping following upper-limb amputation and subsequent targeted reinnervation: A case report. NEUROIMAGE-CLINICAL 2015; 8:329-36. [PMID: 26106558 PMCID: PMC4473101 DOI: 10.1016/j.nicl.2015.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/31/2014] [Accepted: 01/03/2015] [Indexed: 11/30/2022]
Abstract
This case study demonstrates the change of sensory cortical representations of the residual parts of the arm in an individual who underwent a trans-humeral amputation and subsequent targeted reinnervation (TR). As a relatively new surgical technique, TR restores a direct neural connection from amputated sensorimotor nerves to specific target muscles. This method has been successfully applied to upper-limb and lower-limb amputees, and has shown effectiveness in regaining control signals via the newly re-innervated muscles. Correspondingly, recent study results have shown that motor representations for the missing limb move closer to their original locations following TR. Besides regaining motor control signals, TR also restores the sensation in the re-innervated skin areas. We therefore hypothesize that TR causes analogous cortical sensory remapping that may return closer to their original locations. In order to test this hypothesis, cortical activity in response to sensory-level electrical stimulation in different parts of the arm was studied longitudinally in one amputated individual before and up to 2 years after TR. Our results showed that 1) before TR, the cortical response to sensory electrical stimulation in the residual limb showed a diffuse bilateral pattern without a clear focus in either the time or spatial domain; and 2) 2 years after TR, the sensory map of the reinnervated median nerve reorganized, showing predominant activity over the contralateral S1 hand area as well as moderate activity over the ipsilateral S1. Therefore, this work provides new evidence for long-term sensory cortical plasticity in the human brain after TR. We studied sensory cortical mapping before and after targeted reinnervation (TR). EEG was recorded when stimulating the intact finger and the residual nerve. The experiment was repeated longitudinally through 2 years in a single subject. The missing finger representation changed back to a more normal pattern post-TR. Neural mechanisms underlying TR-induced sensory cortical remapping are discussed.
Collapse
Affiliation(s)
- Jun Yao
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, IL, USA
| | - Albert Chen
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, IL, USA ; Department of Biomedical Engineering, Northwestern University, IL, USA
| | - Todd Kuiken
- Department of Biomedical Engineering, Northwestern University, IL, USA ; Department of Physical Medicine and Rehabilitation, Northwestern University, IL, USA ; Center for Bionic Medicine, Rehabilitation Institute of Chicago, IL, USA
| | - Carolina Carmona
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, IL, USA
| | - Julius Dewald
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, IL, USA ; Department of Biomedical Engineering, Northwestern University, IL, USA ; Department of Physical Medicine and Rehabilitation, Northwestern University, IL, USA
| |
Collapse
|
29
|
Tamè L, Pavani F, Papadelis C, Farnè A, Braun C. Early integration of bilateral touch in the primary somatosensory cortex. Hum Brain Mapp 2014; 36:1506-23. [PMID: 25514844 DOI: 10.1002/hbm.22719] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 11/30/2014] [Accepted: 12/01/2014] [Indexed: 11/06/2022] Open
Abstract
Animal, as well as behavioural and neuroimaging studies in humans have documented integration of bilateral tactile information at the level of primary somatosensory cortex (SI). However, it is still debated whether integration in SI occurs early or late during tactile processing, and whether it is somatotopically organized. To address both the spatial and temporal aspects of bilateral tactile processing we used magnetoencephalography in a tactile repetition-suppression paradigm. We examined somatosensory evoked-responses produced by probe stimuli preceded by an adaptor, as a function of the relative position of adaptor and probe (probe always at the left index finger; adaptor at the index or middle finger of the left or right hand) and as a function of the delay between adaptor and probe (0, 25, or 125 ms). Percentage of response-amplitude suppression was computed by comparing paired (adaptor + probe) with single stimulations of adaptor and probe. Results show that response suppression varies differentially in SI and SII as a function of both spatial and temporal features of the stimuli. Remarkably, repetition suppression of SI activity emerged early in time, regardless of whether the adaptor stimulus was presented on the same and the opposite body side with respect to the probe. These novel findings support the notion of an early and somatotopically organized inter-hemispheric integration of tactile information in SI.
Collapse
Affiliation(s)
- Luigi Tamè
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | | | | | | | | |
Collapse
|
30
|
Brodie SM, Borich MR, Boyd LA. Impact of 5-Hz rTMS over the primary sensory cortex is related to white matter volume in individuals with chronic stroke. Eur J Neurosci 2014; 40:3405-12. [PMID: 25223991 DOI: 10.1111/ejn.12717] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/29/2014] [Accepted: 08/08/2014] [Indexed: 12/01/2022]
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that may facilitate mechanisms of motor learning. In a recent single-blind, pseudo-randomized study, we showed that 5-Hz rTMS over ipsilesional primary somatosensory cortex followed by practice of a skilled motor task enhanced motor learning compared with sham rTMS + practice in individuals with chronic stroke. However, the beneficial effect of stimulation was inconsistent. The current study examined how differences in sensorimotor cortex morphology might predict rTMS-related improvements in motor learning in these individuals. High-resolution T1-weighted magnetic resonance images were acquired and processed in FreeSurfer using a newly developed automated, whole brain parcellation technique. Gray matter and white matter volumes of the ipsilesional primary somatosensory and motor cortices were extracted. A significant positive association was observed between the volume of white matter in the primary somatosensory cortex and motor learning-related change, exclusively in the group that received active 5-Hz rTMS. A regression model with age, gray matter and white matter volumes as predictors was significant for predicting motor learning-related change in individuals who received active TMS. White matter volume predicted the greatest amount of variance (47.6%). The same model was non-significant when volumes of the primary motor cortex were considered. We conclude that white matter volume in the cortex underlying the TMS coil may be a novel predictor for behavioral response to 5-Hz rTMS over the ipsilesional primary somatosensory followed by motor practice.
Collapse
Affiliation(s)
- Sonia M Brodie
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Wesbrook Mall, Vancouver, BC, Canada, V6T 1Z3
| | | | | |
Collapse
|
31
|
Schweisfurth MA, Frahm J, Schweizer R. Individual fMRI maps of all phalanges and digit bases of all fingers in human primary somatosensory cortex. Front Hum Neurosci 2014; 8:658. [PMID: 25228867 PMCID: PMC4151507 DOI: 10.3389/fnhum.2014.00658] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/06/2014] [Indexed: 11/30/2022] Open
Abstract
This study determined the individual maps of all fingers in Brodmann area 3b of the human primary somatosensory cortex in a single fMRI session by tactile stimulation at 19 sites across all phalanges and digit bases of the 5 right-hand digits. To quantify basic features of the digit maps within and across subjects, we applied standard descriptive measures, but also implemented a novel quantitative analysis. This so-called Direction/Order (DiOr) method tested whether subjects exhibited an ordering of peak fMRI representations along their individual direction of alignment through the set of analyzed phalanges and whether these individual directions were similar across subjects. Across-digit analysis demonstrated that for each set of homologous phalanges, the D5-to-D1 representations were successively represented along a common direction of alignment. Hence, the well-known mediolateral D5-to-D1 somatotopy was not only confirmed for the distal phalanges (p1), but could also be shown for the medial (p2) and proximal phalanges (p3). In contrast, the peak activation for the digit bases (p4) only partly elicited that digit succession. Complementary, intra-digit analysis revealed a divergent picture of map topography for the different digits. Within D5 (and in a trend: D4), an ordered p1-to-p3 succession was found across subjects, pointing to a consistent intra-digit somatotopy for D5, with p3 generally found medial-posterior to p1. In contrast, for D1, D2, and D3, most subjects did not present with ordered p1-to-p3 maps nor were directions of alignment similarly oriented between subjects. These digits therefore exhibited highly diverse representation patterns across subjects.
Collapse
Affiliation(s)
- Meike A Schweisfurth
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie Göttingen, Germany ; Cognitive Neuroscience Laboratory, German Primate Center Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie Göttingen, Germany
| | - Renate Schweizer
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie Göttingen, Germany
| |
Collapse
|
32
|
Brodie SM, Meehan S, Borich MR, Boyd LA. 5 Hz repetitive transcranial magnetic stimulation over the ipsilesional sensory cortex enhances motor learning after stroke. Front Hum Neurosci 2014; 8:143. [PMID: 24711790 PMCID: PMC3968757 DOI: 10.3389/fnhum.2014.00143] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 02/26/2014] [Indexed: 11/21/2022] Open
Abstract
Sensory feedback is critical for motor learning, and thus to neurorehabilitation after stroke. Whether enhancing sensory feedback by applying excitatory repetitive transcranial magnetic stimulation (rTMS) over the ipsilesional primary sensory cortex (IL-S1) might enhance motor learning in chronic stroke has yet to be investigated. The present study investigated the effects of 5 Hz rTMS over IL-S1 paired with skilled motor practice on motor learning, hemiparetic cutaneous somatosensation, and motor function. Individuals with unilateral chronic stroke were pseudo-randomly divided into either Active or Sham 5 Hz rTMS groups (n = 11/group). Following stimulation, both groups practiced a Serial Tracking Task (STT) with the hemiparetic arm; this was repeated for 5 days. Performance on the STT was quantified by response time, peak velocity, and cumulative distance tracked at baseline, during the 5 days of practice, and at a no-rTMS retention test. Cutaneous somatosensation was measured using two-point discrimination. Standardized sensorimotor tests were performed to assess whether the effects might generalize to impact hemiparetic arm function. The active 5 Hz rTMS + training group demonstrated significantly greater improvements in STT performance {response time [F(1, 286.04) = 13.016, p < 0.0005], peak velocity [F(1, 285.95) = 4.111, p = 0.044], and cumulative distance [F(1, 285.92) = 4.076, p = 0.044]} and cutaneous somatosensation [F(1, 21.15) = 8.793, p = 0.007] across all sessions compared to the sham rTMS + training group. Measures of upper extremity motor function were not significantly different for either group. Our preliminary results suggest that, when paired with motor practice, 5 Hz rTMS over IL-S1 enhances motor learning related change in individuals with chronic stroke, potentially as a consequence of improved cutaneous somatosensation, however no improvement in general upper extremity function was observed.
Collapse
Affiliation(s)
- Sonia M Brodie
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia Vancouver, BC, Canada
| | - Sean Meehan
- School of Kinesiology, University of Michigan Ann Arbor, MI, USA
| | - Michael R Borich
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia Vancouver, BC, Canada
| | - Lara A Boyd
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia Vancouver, BC, Canada
| |
Collapse
|
33
|
Omrani M, Lak A, Diamond ME. Learning not to feel: reshaping the resolution of tactile perception. Front Syst Neurosci 2013; 7:29. [PMID: 23847478 PMCID: PMC3701118 DOI: 10.3389/fnsys.2013.00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 06/14/2013] [Indexed: 11/13/2022] Open
Abstract
We asked whether biased feedback during training could cause human subjects to lose perceptual acuity in a vibrotactile frequency discrimination task. Prior to training, we determined each subject's vibration frequency discrimination capacity on one fingertip, the Just Noticeable Difference (JND). Subjects then received 850 trials in which they performed a same/different judgment on two vibrations presented to that fingertip. They gained points whenever their judgment matched the computer-generated feedback on that trial. Feedback, however, was biased: the probability per trial of “same” feedback was drawn from a normal distribution with standard deviation twice as wide as the subject's JND. After training, the JND was significantly widened: stimulus pairs previously perceived as different were now perceived as the same. The widening of the JND extended to the untrained hand, indicating that the decrease in resolution originated in non-topographic brain regions. In sum, the acuity of subjects' sensory-perceptual systems shifted in order to match the feedback received during training.
Collapse
Affiliation(s)
- Mohsen Omrani
- Tactile Perception and Learning Lab, International School for Advanced Studies-SISSA Trieste, Italy ; School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM) Tehran, Iran ; Centre for Neuroscience Studies, Queen's University Kingston, ON, Canada
| | | | | |
Collapse
|
34
|
Kalberlah C, Villringer A, Pleger B. Dynamic causal modeling suggests serial processing of tactile vibratory stimuli in the human somatosensory cortex--an fMRI study. Neuroimage 2013; 74:164-71. [PMID: 23435215 DOI: 10.1016/j.neuroimage.2013.02.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 02/08/2013] [Accepted: 02/12/2013] [Indexed: 01/18/2023] Open
Abstract
Sensitivity to location and frequency of tactile stimuli is a characterizing feature of human primary (S1), and secondary (S2) somatosensory cortices. Recent evidence suggests that S1 is predominantly receptive to stimulus location, while S2 is attuned to stimulus frequency. Although it is well established in humans that tactile frequency information is relayed serially from S1 to S2, a recent study, using functional magnetic resonance imaging (fMRI) in combination with dynamic causal modeling (DCM), suggested that somatosensory inputs are processed in parallel in S1 and S2. In the present fMRI/DCM study, we revisited this controversy and investigated the specialization of the human somatosensory cortical areas with regard to tactile stimulus representations, as well as their effective connectivity. During brain imaging, 14 participants performed a somatosensory discrimination task on vibrotactile stimuli. Importantly, the model space for DCM was chosen to allow for direct inference on the question of interest by systematically varying the information transmission from pure parallel to pure serial implementations. Bayesian model comparison on the level of model families strongly favors a serial, instead of a parallel processing route for tactile stimulus information along the somatosensory pathway. Our fMRI/DCM data thus support previous suggestions of a sequential information transmission from S1 to S2 in humans.
Collapse
Affiliation(s)
- Christian Kalberlah
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | | | | |
Collapse
|
35
|
Abstract
Topographic maps of the receptive surface are a fundamental feature of neural organization in many sensory systems. While touch is finely mapped in the cerebral cortex, it remains controversial how precise any cortical nociceptive map may be. Given that nociceptive innervation density is relatively low on distal skin regions such as the digits, one might conclude that the nociceptive system lacks fine representation of these regions. Indeed, only gross spatial organization of nociceptive maps has been reported so far. However, here we reveal the existence of fine-grained somatotopy for nociceptive inputs to the digits in human primary somatosensory cortex (SI). Using painful nociceptive-selective laser stimuli to the hand, and phase-encoded functional magnetic resonance imaging analysis methods, we observed somatotopic maps of the digits in contralateral SI. These nociceptive maps were highly aligned with maps of non-painful tactile stimuli, suggesting comparable cortical representations for, and possible interactions between, mechanoreceptive and nociceptive signals. Our findings may also be valuable for future studies tracking the time course and the spatial pattern of plastic changes in cortical organization involved in chronic pain.
Collapse
|
36
|
Tamè L, Braun C, Lingnau A, Schwarzbach J, Demarchi G, Li Hegner Y, Farnè A, Pavani F. The Contribution of Primary and Secondary Somatosensory Cortices to the Representation of Body Parts and Body Sides: An fMRI Adaptation Study. J Cogn Neurosci 2012; 24:2306-20. [DOI: 10.1162/jocn_a_00272] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
Although the somatosensory homunculus is a classically used description of the way somatosensory inputs are processed in the brain, the actual contributions of primary (SI) and secondary (SII) somatosensory cortices to the spatial coding of touch remain poorly understood. We studied adaptation of the fMRI BOLD response in the somatosensory cortex by delivering pairs of vibrotactile stimuli to the finger tips of the index and middle fingers. The first stimulus (adaptor) was delivered either to the index or to the middle finger of the right or left hand, and the second stimulus (test) was always administered to the left index finger. The overall BOLD response evoked by the stimulation was primarily contralateral in SI and was more bilateral in SII. However, our fMRI adaptation approach also revealed that both somatosensory cortices were sensitive to ipsilateral as well as to contralateral inputs. SI and SII adapted more after subsequent stimulation of homologous as compared with nonhomologous fingers, showing a distinction between different fingers. Most importantly, for both somatosensory cortices, this finger-specific adaptation occurred irrespective of whether the tactile stimulus was delivered to the same or to different hands. This result implies integration of contralateral and ipsilateral somatosensory inputs in SI as well as in SII. Our findings suggest that SI is more than a simple relay for sensory information and that both SI and SII contribute to the spatial coding of touch by discriminating between body parts (fingers) and by integrating the somatosensory input from the two sides of the body (hands).
Collapse
Affiliation(s)
- Luigi Tamè
- 1University of Trento
- 2University of Reading
| | | | | | | | | | | | - Alessandro Farnè
- 4INSERM U1028, CNRS UMR5292, Bron, France
- 5Université Claude Bernard Lyon I, Lyon, F-69000, France
| | | |
Collapse
|
37
|
Martuzzi R, van der Zwaag W, Farthouat J, Gruetter R, Blanke O. Human finger somatotopy in areas 3b, 1, and 2: a 7T fMRI study using a natural stimulus. Hum Brain Mapp 2012; 35:213-26. [PMID: 22965769 DOI: 10.1002/hbm.22172] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/23/2011] [Accepted: 07/10/2012] [Indexed: 11/07/2022] Open
Abstract
To study the properties of human primary somatosensory (S1) cortex as well as its role in cognitive and social processes, it is necessary to noninvasively localize the cortical representations of the body. Being arguably the most relevant body parts for tactile exploration, cortical representations of fingers are of particular interest. The aim of the present study was to investigate the cortical representation of individual fingers (D1-D5), using human touch as a stimulus. Utilizing the high BOLD sensitivity and spatial resolution at 7T, we found that each finger is represented within three subregions of S1 in the postcentral gyrus. Within each of these three areas, the fingers are sequentially organized (from D1 to D5) in a somatotopic manner. Therefore, these finger representations likely reflect distinct activations of BAs 3b, 1, and 2, similar to those described in electrophysiological work in non-human primates. Quantitative analysis of the local BOLD responses revealed that within BA3b, each finger representation is specific to its own stimulation without any cross-finger responsiveness. This finger response selectivity was less prominent in BA 1 and in BA 2. A test-retest procedure highlighted the reproducibility of the results and the robustness of the method for BA 3b. Finally, the representation of the thumb was enlarged compared to the other fingers within BAs 1 and 2. These findings extend previous human electrophysiological and neuroimaging data but also reveal differences in the functional organization of S1 in human and nonhuman primates.
Collapse
Affiliation(s)
- Roberto Martuzzi
- Laboratory of Cognitive Neuroscience, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Center for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | | | | | | | | |
Collapse
|
38
|
Song S, Sandrini M, Cohen LG. Modifying somatosensory processing with non-invasive brain stimulation. Restor Neurol Neurosci 2012; 29:427-37. [PMID: 22124034 DOI: 10.3233/rnn-2011-0614] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Purposeful manipulation of cortical plasticity and excitability within somatosensory regions may have therapeutic potential. Non-invasive brain stimulation (NBS) techniques such as transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) have shown promise towards this end with certain NBS protocols augmenting somatosensory processing and others down-regulating it. Here, we review NBS protocols which, when applied to primary somatosensory cortex, facilitate cortical excitability and tactile acuity (i.e., high-frequency repetitive TMS (rTMS), intermittent theta burst stimulation (TBS), paired associative stimulation (PAS) N20-5 to 0, anodal tDCS), and protocols that inhibit the same (i.e., low-frequency rTMS, continuous TBS, PAS N20-20, cathodal tDCS). Other studies have targeted multisensory regions of the brain to modulate somatosensory processing. These studies in full present a wide array of strategies in which NBS can be utilized to influence somatosensory processing in a behaviorally and clinically relevant capacity.
Collapse
Affiliation(s)
- Sunbin Song
- Human Cortical Physiology and Stroke Neurorehabilitation Section, NINDS, NIH, MD20892, USA
| | | | | |
Collapse
|
39
|
Ageberg E, Björkman A, Rosén B, Roos EM. Principles of brain plasticity in improving sensorimotor function of the knee and leg in patients with anterior cruciate ligament injury: a double-blind randomized exploratory trial. BMC Musculoskelet Disord 2012; 13:68. [PMID: 22574814 PMCID: PMC3441769 DOI: 10.1186/1471-2474-13-68] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 03/13/2012] [Indexed: 12/26/2022] Open
Abstract
Background Severe traumatic knee injury, including injury to the anterior cruciate ligament (ACL), leads to impaired sensorimotor function. Although improvements are achieved by training, impairment often persists. Because good sensorimotor function is associated with better patient-reported function and a potential lower risk of future joint problems, more effective treatment is warranted. Temporary cutaneous anesthesia of adjacent body parts was successfully used on the hand and foot to improve sensorimotor function. The aim of this study was to test whether this principle of brain plasticity could be used on the knee. The hypothesis was that temporary anesthesia of the skin area above and below the knee would improve sensorimotor function of the ipsilateral knee and leg in subjects with ACL injury. Methods In this double-blind exploratory study, 39 subjects with ACL injury (mean age 24 years, SD 5.2, 49% women, mean 52 weeks after injury or reconstruction) and self-reported functional limitations and lack of trust in the knee were randomized to temporary local cutaneous application of anesthetic (EMLA®) (n = 20) or placebo cream (n = 19). Fifty grams of EMLA®, or placebo, was applied on the leg 10 cm above and 10 cm below the center of patella, leaving the area around the knee without cream. Measures of sensory function (perception of touch, vibration sense, knee kinesthesia) and motor function (knee muscle strength, hop test) were assessed before and after 90 minutes of treatment with EMLA® or placebo. The paired t-test was used for comparisons within groups and analysis of variance between groups, except for ordinal data where the Wilcoxon signed rank test, or Mann–Whitney test, was used. The number of subjects needed was determined by an a priori sample size calculation. Results No statistically significant or clinically relevant differences were seen over time (before vs. after) in the measures of sensory or motor functions in the EMLA® group or in the placebo group. There were no differences between the groups due to treatment effect (EMLA® vs. placebo). Conclusions Temporary cutaneous anesthesia of adjacent body parts had no effect in improving sensorimotor function of the knee and leg in subjects with severe traumatic knee ligament injury.
Collapse
Affiliation(s)
- Eva Ageberg
- Department of Orthopedics, Clinical Sciences Lund, Lund University, Lund, Sweden.
| | | | | | | |
Collapse
|
40
|
Habermehl C, Holtze S, Steinbrink J, Koch SP, Obrig H, Mehnert J, Schmitz CH. Somatosensory activation of two fingers can be discriminated with ultrahigh-density diffuse optical tomography. Neuroimage 2011; 59:3201-11. [PMID: 22155031 DOI: 10.1016/j.neuroimage.2011.11.062] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 11/01/2011] [Accepted: 11/21/2011] [Indexed: 11/30/2022] Open
Abstract
Topographic non-invasive near infrared spectroscopy (NIRS) has become a well-established tool for functional brain imaging. Applying up to 100 optodes over the head of a subject, allows achieving a spatial resolution in the centimeter range. This resolution is poor compared to other functional imaging tools. However, recently it was shown that diffuse optical tomography (DOT) as an extension of NIRS based on high-density (HD) probe arrays and supplemented by an advanced image reconstruction procedure allows describing activation patterns with a spatial resolution in the millimeter range. Building on these findings, we hypothesize that HD-DOT may render very focal activations accessible which would be missed by the traditionally used sparse arrays. We examined activation patterns in the primary somatosensory cortex, since its somatotopic organization is very fine-grained. We performed a vibrotactile stimulation study of the first and fifth finger in eight human subjects, using a 900-channel continuous-wave DOT imaging system for achieving a higher resolution than conventional topographic NIRS. To compare the results to a well-established high-resolution imaging technique, the same paradigm was investigated in the same subjects by means of functional magnetic resonance imaging (fMRI). In this work, we tested the advantage of ultrahigh-density probe arrays and show that highly focal activations would be missed by classical next-nearest neighbor NIRS approach, but also by DOT, when using a sparse probe array. Distinct activation patterns for both fingers correlated well with the expected neuroanatomy in five of eight subjects. Additionally we show that activation for different fingers is projected to different tissue depths in the DOT image. Comparison to the fMRI data yielded similar activation foci in seven out of ten finger representations in these five subjects when comparing the lateral localization of DOT and fMRI results.
Collapse
Affiliation(s)
- Christina Habermehl
- Berlin NeuroImaging Center, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
| | | | | | | | | | | | | |
Collapse
|
41
|
Burton H, Agato A, Sinclair RJ. Repetition learning of vibrotactile temporal sequences: an fMRI study in blind and sighted individuals. Brain Res 2011; 1433:69-79. [PMID: 22154406 DOI: 10.1016/j.brainres.2011.11.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 11/15/2011] [Accepted: 11/18/2011] [Indexed: 11/17/2022]
Abstract
The present fMRI study examined cortical activity to repeated vibrotactile sequences in 11 early blind and 11 sighted participants. All participants performed with >90% accuracy and showed practice induced improvement with faster reaction times in identifying matched and unmatched vibrotactile sequences. In blind only, occipital/temporal and parietal/somatosensory cortices showed practice induced reductions in positive BOLD amplitudes that possibly reflected repetition induced learning effects. The significant findings in occipital cortex of the blind indicated that perceptual processing of tactile inputs in visually deprived cortex is dynamic as response amplitudes changed with practice. Thus, stimulus processing became more efficient. It was hypothesized that the changes in occipital cortex of the blind reflected life-long skill in processing somatosensory inputs. Both groups showed activity reductions with practice in mid/posterior ventrolateral prefrontal cortex. These activity reductions suggested common stimulus-response learning associations for vibrotactile sequences in mid/posterior ventrolateral prefrontal cortex.
Collapse
Affiliation(s)
- Harold Burton
- Department of Anatomy and Neurobiology, Washington University School of Medicine, USA.
| | | | | |
Collapse
|
42
|
Chen LM, Dillenburger BC, Wang F, Tang CH. Differential fMRI activation to noxious heat and tactile stimuli in parasylvian areas of new world monkeys. Pain 2011; 153:158-169. [PMID: 22115923 DOI: 10.1016/j.pain.2011.10.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 09/06/2011] [Accepted: 10/04/2011] [Indexed: 10/15/2022]
Abstract
Emerging evidence supports an important role of posterior parasylvian areas in both pain and touch processing. Whether there are separate or shared networks for these sensations remains controversial. The present study compared spatial patterns of brain activation in response to unilateral nociceptive heat (47.5°C) or innocuous tactile stimulation (8-Hz vibration) to digits through high-resolution functional magnetic resonance imaging (fMRI) in squirrel monkeys. In addition, the temporal profile of heat-stimulus-evoked fMRI Blood Oxygenation Level Dependent (BOLD) signal changes was characterized. By examining high-resolution fMRI and histological measures at both the individual and the group levels, we found that both nociceptive heat and tactile stimuli elicited activation in bilateral secondary somatosensory and ventral parietal areas (S2/PV) and in ipsilateral ventral somatosensory areas (VS) and retroinsula (Ri). Bilateral posterior insular cortex (pIns) and area 7b responded preferentially to nociceptive heat stimulation. Single voxels within each activation cluster showed robust BOLD signal changes during each block of nociceptive stimulation. Across animals (n=11), nociceptive response magnitudes of contralateral VS and pIns and ipsilateral Ri were significantly greater than corresponding areas in the opposite hemisphere. In sum, both distinct and shared areas in regions surrounding the posterior sylvian fissure were activated in response to nociceptive and tactile inputs in nonhuman primates.
Collapse
Affiliation(s)
- Li Min Chen
- Department of Radiology and Radiological Science, Vanderbilt University, Nashville, TN, USA Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
| | | | | | | |
Collapse
|
43
|
Arima T, Yanagi Y, Niddam DM, Ohata N, Arendt-Nielsen L, Minagi S, Sessle BJ, Svensson P. Corticomotor plasticity induced by tongue-task training in humans: a longitudinal fMRI study. Exp Brain Res 2011; 212:199-212. [PMID: 21590261 DOI: 10.1007/s00221-011-2719-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 04/27/2011] [Indexed: 11/25/2022]
Abstract
Corticomotor pathways may undergo neuroplastic changes in response to acquisition of new motor skills. Little is known about the motor control strategies for learning new tongue tasks. The aim of this study was to investigate the longitudinal effect of novel tongue-task training on corticomotor neuroplasticity. Thirteen healthy, right-handed men, aged 24-35 years (mean age ± SD: 27.3 ± 0.3 years), performed a training task consisting of standardized tongue protrusion onto a force transducer. The tongue task consisted of a relax-protrude-hold-relax cycle with 1.0 N as the target at the hold phase lasting for 1.5 s. Subjects repeated this task for 1 h. Functional magnetic resonance imaging was carried out before the tongue-task training (baseline), 1-h after the training, and one-day and one-week follow-up. During scanning, the subjects performed tongue protrusion in blocks interspersed with rest. A region-of-interest (ROI) approach and an explorative search were implemented for the analysis of corticomotor activity across conditions. All subjects completed the tongue-task training (mean success rate 43.0 ± 13.2%). In the baseline condition, tongue protrusion resulted in bilateral activity in regions most typically associated with a motor task including medial frontal gyrus (supplementary motor area [SMA]), precentral gyrus (tongue motor cortex), putamen, thalamus, and cerebellum. The ROI analysis revealed increased activity in the precentral gyrus already 1 h post-training. One day after the training, increased activity was observed in the precentral gyrus, SMA, putamen, and cerebellum. No increase was found 1 week after training. Correlation analyses between changes in success rates and changes in the numbers of voxels showed robust associations for left Area 4a in primary motor cortex 1 h, 1 day, and 1 week after the tongue-task training and for the left Area 4p in primary motor cortex and the left lateral premotor cortex 1 day after the training. In the unrestricted analysis, increased activity was found in the parahippocampal gyrus 1 h after the tongue-task training and remained for a week. Decreased activity was found in right post-central and middle frontal gyri 1 h and 1 week post-training. The results verified the involvement of specific corticomotor areas in response to tongue protrusion. Short-term tongue-task training was associated with longer-lasting (up to 1 week) changes in motor-related brain activity. The results suggested that primary motor areas are involved in the early and late stages, while other motor areas mainly are engaged in the later stage of corticomotor neuroplasticity of the tongue.
Collapse
Affiliation(s)
- Taro Arima
- Department of Oral Rehabilitation, Graduate School of Dental Medicine, University of Hokkaido, Sapporo, Japan
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Functional MRI indicates consistent intra-digit topographic maps in the little but not the index finger within the human primary somatosensory cortex. Neuroimage 2011; 56:2138-43. [PMID: 21421062 DOI: 10.1016/j.neuroimage.2011.03.038] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 03/10/2011] [Accepted: 03/14/2011] [Indexed: 11/22/2022] Open
Abstract
This study explored the question of intra-digit somatotopy of sensory representations in the little and index finger of 10 subjects using tactile stimulation of the fingertip (p1) and base (p4) and functional magnetic resonance imaging (fMRI) at 1.5mm isotropic spatial resolution. The Euclidian distances between p1 and p4 peak representations in Brodmann area 3b resulted in 5.0±0.7mm for the little finger and 6.7±0.5mm for the index finger. These non-collocated representations were found to be consistently ordered across subjects for the little but not the index finger. When using separate distances for medial-lateral, anterior-posterior, and inferior-superior orientations, p4 was 1.9±0.7mm medial to p1 for the little finger in agreement with findings in macaque monkeys, whereas no consistent intra-digit somatotopy across subjects was found for the index finger. This discrepancy could point to differences in the map-forming processes based on sensory input. On the behavioral level it may be attributed to our everyday use of the hand, for which p4 of the index finger plays a much less important role than p4 of the little finger, which is located at the outer border of the hand.
Collapse
|
45
|
Wingert JR, Sinclair RJ, Dixit S, Damiano DL, Burton H. Somatosensory-evoked cortical activity in spastic diplegic cerebral palsy. Hum Brain Mapp 2011; 31:1772-85. [PMID: 20205249 DOI: 10.1002/hbm.20977] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Somatosensory deficits have been identified in cerebral palsy (CP), but associated cortical brain activity in CP remains poorly understood. Functional MRI was used to measure blood oxygenation level-dependent (BOLD) responses during three tactile tasks in 10 participants with spastic diplegia (mean age: 18.70 years, SD: 7.99 years; 5 females) and 10 age-matched controls (mean age: 18.60 years, SD: 3.86 years; 5 females). Tactile stimulation involved servo-controlled translation of smooth or embossed surfaces across the right index finger pad; the discrimination tasks with embossed surfaces involved judging whether (1) paired shapes were similar or different, and (2) a rougher set of horizontal gratings preceded or followed a smoother one. Velocity and duration of surface translation was identical across all trials. In addition, an event-related design revealed response dynamics per trial in both groups. Compared to controls, individuals with spastic diplegia had significantly reduced spatial extents in activated cortical areas and smaller BOLD response magnitudes in cortical areas for somatosensation, motor, and goal-directed/attention behaviors. These results provide mechanisms for the widespread somatosensory deficits in CP. The reduced activation noted across multiple cortical areas might contribute to motor deficits in CP.
Collapse
Affiliation(s)
- Jason R Wingert
- Department of Health and Wellness, University of North Carolina at Asheville, One University Heights, Asheville, North Carolina 28804, USA.
| | | | | | | | | |
Collapse
|
46
|
Stringer EA, Chen LM, Friedman RM, Gatenby C, Gore JC. Differentiation of somatosensory cortices by high-resolution fMRI at 7 T. Neuroimage 2010; 54:1012-20. [PMID: 20887793 DOI: 10.1016/j.neuroimage.2010.09.058] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/16/2010] [Accepted: 09/21/2010] [Indexed: 11/28/2022] Open
Abstract
This study aimed to evaluate the ability of BOLD signals at high MRI field (7 T) to map fine-scale single-digit activations in subdivisions (areas 3b and 1) of the human primary somatosensory cortex (SI) in individual subjects. We acquired BOLD fMRI data from cortical areas around the central suclus in six healthy human subjects while stimulating individual finger pads with 2-Hz air puffs. Discrete, single-digit responses were identified in an area along the posterior bank of the central sulcus corresponding to area 3b and in an area along the crest of the postcentral gyrus corresponding to area 1. In single subjects, activations of digits 1 to 4 in both areas 3b and 1 were organized in a somatotopic manner. The separation of digit representations was measured for adjacent digits and was approximately 1.6 times greater in area 3b than in area 1. Within individual subjects, the cortical responses to single-digit stimulations and the magnitude of the BOLD signals were reproducible across imaging runs and were comparable across subjects. Our findings demonstrate that BOLD fMRI at 7 T is capable of revealing the somatotopic organization of single-digit activations with good within-subject reliability and reproducibility, and activation maps can be acquired within a reasonably short time window, which are essential characteristics for several neurological applications within patient populations.
Collapse
|
47
|
Eshel N, Ruff CC, Spitzer B, Blankenburg F, Driver J. Effects of parietal TMS on somatosensory judgments challenge interhemispheric rivalry accounts. Neuropsychologia 2010; 48:3470-81. [PMID: 20678510 PMCID: PMC2956832 DOI: 10.1016/j.neuropsychologia.2010.07.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Revised: 06/30/2010] [Accepted: 07/26/2010] [Indexed: 01/14/2023]
Abstract
Interplay between the cerebral hemispheres is vital for coordinating perception and behavior. One influential account holds that the hemispheres engage in rivalry, each inhibiting the other. In the somatosensory domain, a seminal paper claimed to demonstrate such interhemispheric rivalry, reporting improved tactile detection sensitivity on the right hand after transcranial magnetic stimulation (TMS) to the right parietal lobe (Seyal, Ro, & Rafal, 1995). Such improvement in tactile detection ipsilateral to TMS could follow from interhemispheric rivalry, if one assumes that TMS disrupted cortical processing under the coil and thereby released the other hemisphere from inhibition. Here we extended the study by Seyal et al. (1995) to determine the effects of right parietal TMS on tactile processing for either hand, rather than only the ipsilateral hand. We performed two experiments applying TMS in the context of median-nerve stimulation; one experiment required somatosensory detection, the second somatosensory intensity discrimination. We found different TMS effects on detection versus discrimination, but neither set of results followed the prediction from hemispheric rivalry that enhanced performance for one hand should invariably be associated with impaired performance for the other hand, and vice-versa. Our results argue against a strict rivalry interpretation, instead suggesting that parietal TMS can provide a pedestal-like increment in somatosensory response.
Collapse
Affiliation(s)
- Neir Eshel
- UCL Institute of Cognitive Neuroscience, University College London, London, UK.
| | | | | | | | | |
Collapse
|
48
|
Koch SP, Habermehl C, Mehnert J, Schmitz CH, Holtze S, Villringer A, Steinbrink J, Obrig H. High-resolution optical functional mapping of the human somatosensory cortex. FRONTIERS IN NEUROENERGETICS 2010; 2:12. [PMID: 20616883 PMCID: PMC2899520 DOI: 10.3389/fnene.2010.00012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 05/26/2010] [Indexed: 11/19/2022]
Abstract
Non-invasive optical imaging of brain function has been promoted in a number of fields in which functional magnetic resonance imaging (fMRI) is limited due to constraints induced by the scanning environment. Beyond physiological and psychological research, bedside monitoring and neurorehabilitation may be relevant clinical applications that are yet little explored. A major obstacle to advocate the tool in clinical research is insufficient spatial resolution. Based on a multi-distance high-density optical imaging setup, we here demonstrate a dramatic increase in sensitivity of the method. We show that optical imaging allows for the differentiation between activations of single finger representations in the primary somatosensory cortex (SI). Methodologically our findings confirm results in a pioneering study by Zeff et al. (2007) and extend them to the homuncular organization of SI. After performing a motor task, eight subjects underwent vibrotactile stimulation of the little finger and the thumb. We used a high-density diffuse-optical sensing array in conjunction with optical tomographic reconstruction. Optical imaging disclosed three discrete activation foci one for motor and two discrete foci for vibrotactile stimulation of the first and fifth finger, respectively. The results were co-registered to the individual anatomical brain anatomy (MRI) which confirmed the localization in the expected cortical gyri in four subjects. This advance in spatial resolution opens new perspectives to apply optical imaging in the research on plasticity notably in patients undergoing neurorehabilitation.
Collapse
Affiliation(s)
- Stefan P Koch
- Berlin NeuroImaging Center, Charité Universitätsmedizin Berlin Berlin, Germany
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Temporomandibular disorder modifies cortical response to tactile stimulation. THE JOURNAL OF PAIN 2010; 11:1083-94. [PMID: 20462805 DOI: 10.1016/j.jpain.2010.02.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 01/20/2010] [Accepted: 02/08/2010] [Indexed: 11/24/2022]
Abstract
UNLABELLED Individuals with temporomandibular disorder (TMD) suffer from persistent facial pain and exhibit abnormal sensitivity to tactile stimulation. To better understand the pathophysiological mechanisms underlying TMD, we investigated cortical correlates of this abnormal sensitivity to touch. Using functional magnetic resonance imaging (fMRI), we recorded cortical responses evoked by low-frequency vibration of the index finger in subjects with TMD and in healthy controls (HC). Distinct subregions of contralateral primary somatosensory cortex (SI), secondary somatosensory cortex (SII), and insular cortex responded maximally for each group. Although the stimulus was inaudible, primary auditory cortex was activated in TMDs. TMDs also showed greater activation bilaterally in anterior cingulate cortex and contralaterally in the amygdala. Differences between TMDs and HCs in responses evoked by innocuous vibrotactile stimulation within SI, SII, and the insula paralleled previously reported differences in responses evoked by noxious and innocuous stimulation, respectively, in healthy individuals. This unexpected result may reflect a disruption of the normal balance between central resources dedicated to processing innocuous and noxious input, manifesting itself as increased readiness of the pain matrix for activation by even innocuous input. Activation of the amygdala in our TMD group could reflect the establishment of aversive associations with tactile stimulation due to the persistence of pain. PERSPECTIVE This article presents evidence that central processing of innocuous tactile stimulation is abnormal in TMD. Understanding the complexity of sensory disruption in chronic pain could lead to improved methods for assessing cerebral cortical function in these patients.
Collapse
|
50
|
An extended motor network generates beta and gamma oscillatory perturbations during development. Brain Cogn 2010; 73:75-84. [PMID: 20418003 DOI: 10.1016/j.bandc.2010.03.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 03/01/2010] [Accepted: 03/08/2010] [Indexed: 11/22/2022]
Abstract
This study examines the time course and neural generators of oscillatory beta and gamma motor responses in typically-developing children. Participants completed a unilateral flexion-extension task using each index finger as whole-head magnetoencephalography (MEG) data were acquired. These MEG data were imaged in the frequency-domain using spatial filtering and the resulting event-related synchronizations and desynchronizations (ERS/ERD) were subjected to voxel-wise statistical analyses to illuminate time-frequency specific activation patterns. Consistent with adult data, these children exhibited a pre-movement ERD that was strongest over the contralateral post-central gyrus, and a post-movement ERS response with the most prominent peak being in the contralateral precentral gyrus near premotor cortices. We also observed a high-frequency (approximately 80 Hz) ERS response that coincided with movement onset and was centered on the contralateral precentral gyrus, slightly superior and posterior to the beta ERS. In addition to pre- and post-central gyri activations, these children exhibited beta and gamma activity in supplementary motor areas (SMA) before and during movement, and beta activation in cerebellar cortices before and after movement. We believe the gamma synchronization may be an excellent candidate signal of basic cortical motor control, as the spatiotemporal dynamics indicate the primary motor cortex generates this response (and not the beta oscillations) which is closely yoked to the initial muscle activation. Lastly, these data suggest several additional neural regions including the SMA and cerebellum are involved in basic movements during development.
Collapse
|