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Multi-finger receptive field properties in primary somatosensory cortex: A revised account of the spatiotemporal integration functions of area 3b. Cell Rep 2023; 42:112176. [PMID: 36867529 DOI: 10.1016/j.celrep.2023.112176] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 08/14/2022] [Accepted: 02/11/2023] [Indexed: 03/04/2023] Open
Abstract
The leading view in the somatosensory system indicates that area 3b serves as a cortical relay site that primarily encodes (cutaneous) tactile features limited to individual digits. Our recent work argues against this model by showing that area 3b cells can integrate both cutaneous and proprioceptive information from the hand. Here, we further test the validity of this model by studying multi-digit (MD) integration properties in area 3b. In contrast to the prevailing view, we show that most cells in area 3b have a receptive field (RF) that extends to multiple digits, with the size of the RF (i.e., the number of responsive digits) increasing across time. Further, we show that MD cells' orientation angle preference is highly correlated across digits. Taken together, these data show that area 3b plays a larger role in generating neural representations of tactile objects, as opposed to just being a "feature detector" relay site.
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Enander JM, Jörntell H. Somatosensory Cortical Neurons Decode Tactile Input Patterns and Location from Both Dominant and Non-dominant Digits. Cell Rep 2019; 26:3551-3560.e4. [DOI: 10.1016/j.celrep.2019.02.099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 12/10/2018] [Accepted: 02/22/2019] [Indexed: 10/27/2022] Open
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Delhaye BP, Long KH, Bensmaia SJ. Neural Basis of Touch and Proprioception in Primate Cortex. Compr Physiol 2018; 8:1575-1602. [PMID: 30215864 PMCID: PMC6330897 DOI: 10.1002/cphy.c170033] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The sense of proprioception allows us to keep track of our limb posture and movements and the sense of touch provides us with information about objects with which we come into contact. In both senses, mechanoreceptors convert the deformation of tissues-skin, muscles, tendons, ligaments, or joints-into neural signals. Tactile and proprioceptive signals are then relayed by the peripheral nerves to the central nervous system, where they are processed to give rise to percepts of objects and of the state of our body. In this review, we first examine briefly the receptors that mediate touch and proprioception, their associated nerve fibers, and pathways they follow to the cerebral cortex. We then provide an overview of the different cortical areas that process tactile and proprioceptive information. Next, we discuss how various features of objects-their shape, motion, and texture, for example-are encoded in the various cortical fields, and the susceptibility of these neural codes to attention and other forms of higher-order modulation. Finally, we summarize recent efforts to restore the senses of touch and proprioception by electrically stimulating somatosensory cortex. © 2018 American Physiological Society. Compr Physiol 8:1575-1602, 2018.
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Affiliation(s)
- Benoit P Delhaye
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, USA
| | - Katie H Long
- Committee on Computational Neuroscience, University of Chicago, Chicago, USA
| | - Sliman J Bensmaia
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, USA.,Committee on Computational Neuroscience, University of Chicago, Chicago, USA
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Pálfi E, Zalányi L, Ashaber M, Palmer C, Kántor O, Roe AW, Friedman RM, Négyessy L. Connectivity of neuronal populations within and between areas of primate somatosensory cortex. Brain Struct Funct 2018; 223:2949-2971. [PMID: 29725759 DOI: 10.1007/s00429-018-1671-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/21/2018] [Indexed: 11/25/2022]
Abstract
Functions of the cerebral cortex emerge via interactions of horizontally distributed neuronal populations within and across areas. However, the connectional underpinning of these interactions is not well understood. The present study explores the circuitry of column-size cortical domains within the hierarchically organized somatosensory cortical areas 3b and 1 using tract tracing and optical intrinsic signal imaging (OIS). The anatomical findings reveal that feedforward connections exhibit high topographic specificity, while intrinsic and feedback connections have a more widespread distribution. Both intrinsic and inter-areal connections are topographically oriented across the finger representations. Compared to area 3b, the low clustering of connections and small cortical magnification factor supports that the circuitry of area 1 scaffolds a sparse functional representation that integrates peripheral information from a large area that is fed back to area 3b. Fast information exchange between areas is ensured by thick axons forming a topographically organized, reciprocal pathway. Moreover, the highest density of projecting neurons and groups of axon arborization patches corresponds well with the size and locations of the functional population response reported by OIS. The findings establish connectional motifs at the mesoscopic level that underpin the functional organization of the cerebral cortex.
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Affiliation(s)
- E Pálfi
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, 1094, Hungary
| | - L Zalányi
- Complex Systems and Computational Neuroscience Group, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós út 29-33, Budapest, 1121, Hungary
| | - M Ashaber
- Department of Physiology and Biochemistry, Faculty of Veterinary Science, Szent István University, Budapest, 1078, Hungary
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - C Palmer
- Department of Mathematical Sciences, University of Montana, Missoula, MT, 59812, USA
| | - O Kántor
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, 1094, Hungary
- Department of Neuroanatomy, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, 79104, Freiburg, Germany
| | - A W Roe
- Division of Neuroscience, Oregon Health and Science University, Portland, OR, 97006, USA
- Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University, Hangzhou, 310029, China
| | - R M Friedman
- Division of Neuroscience, Oregon Health and Science University, Portland, OR, 97006, USA
| | - L Négyessy
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, 1094, Hungary.
- Complex Systems and Computational Neuroscience Group, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós út 29-33, Budapest, 1121, Hungary.
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5
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Abstract
Somatosensory areas containing topographic maps of the body surface are a major feature of parietal cortex. In primates, parietal cortex contains four somatosensory areas, each with its own map, with the primary cutaneous map in area 3b. Rodents have at least three parietal somatosensory areas. Maps are not isomorphic to the body surface, but magnify behaviorally important skin regions, which include the hands and face in primates, and the whiskers in rodents. Within each map, intracortical circuits process tactile information, mediate spatial integration, and support active sensation. Maps may also contain fine-scale representations of touch submodalities, or direction of tactile motion. Functional representations are more overlapping than suggested by textbook depictions of map topography. The whisker map in rodent somatosensory cortex is a canonic system for studying cortical microcircuits, sensory coding, and map plasticity. Somatosensory maps are plastic throughout life in response to altered use or injury. This chapter reviews basic principles and recent findings in primate, human, and rodent somatosensory maps.
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Affiliation(s)
- Samuel Harding-Forrester
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States
| | - Daniel E Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States.
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Roe AW, Winberry JE, Friedman RM. Study of single and multidigit activation in monkey somatosensory cortex using voltage-sensitive dye imaging. NEUROPHOTONICS 2017; 4:031219. [PMID: 28573156 PMCID: PMC5446783 DOI: 10.1117/1.nph.4.3.031219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 05/02/2017] [Indexed: 06/02/2023]
Abstract
Toward the goal of understanding cutaneous sensory integration during manual behavior, we used voltage-sensitive dye (VSD) imaging to study the organization and dynamics of anesthetized monkey primary somatosensory cortex (SI) in response to single and multidigit tactile stimulation. We find that in both macaque and squirrel monkey SI, VSD reveals clear focal digit topography consistent with previous electrophysiological and intrinsic signal imaging studies. VSD also reveals interactions in SI in response to multidigit stimulation. With a tactile funneling paradigm in areas 3b and 1 in squirrel monkeys, VSD reveals two-digit induction of subthreshhold influences, consistent with lateral intracortical inhibition. In response to tactile apparent motion stimuli, VSD reveals preferential response to motion stimuli over static tactile stimuli in both areas 1 and 3b. Comparison of the response at different digit locations to "toward digit" stimuli suggests the presence of direction-selective response in area 1; however, further study is needed. These exciting results indicate that VSD constitutes a powerful tool for studying somatosensory cortical processing in nonhuman primates and should be further developed for future somatosensory studies in awake behaving monkeys.
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Affiliation(s)
- Anna Wang Roe
- Zhejiang University, Qiushi Academy for Advanced Studies, Interdisciplinary Institute of Neuroscience and Technology, Hangzhou, China
- Oregon Health and Science University, Oregon National Primate Research Center, Division of Neuroscience, Beaverton, Oregon, United States
- Vanderbilt University, Department of Psychology, Nashville, Tennessee, United States
| | - Jeremy E. Winberry
- Vanderbilt University, Department of Psychology, Nashville, Tennessee, United States
- The University of Chicago, Department of Organismal Biology and Anatomy, Chicago, Illinois, United States
| | - Robert M. Friedman
- Oregon Health and Science University, Oregon National Primate Research Center, Division of Neuroscience, Beaverton, Oregon, United States
- Vanderbilt University, Department of Psychology, Nashville, Tennessee, United States
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Sanchez Panchuelo RM, Ackerley R, Glover PM, Bowtell RW, Wessberg J, Francis ST, McGlone F. Mapping quantal touch using 7 Tesla functional magnetic resonance imaging and single-unit intraneural microstimulation. eLife 2016; 5. [PMID: 27154626 PMCID: PMC4898929 DOI: 10.7554/elife.12812] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 05/06/2016] [Indexed: 11/18/2022] Open
Abstract
Using ultra-high field 7 Tesla (7T) functional magnetic resonance imaging (fMRI), we map the cortical and perceptual responses elicited by intraneural microstimulation (INMS) of single mechanoreceptive afferent units in the median nerve, in humans. Activations are compared to those produced by applying vibrotactile stimulation to the unit’s receptive field, and unit-type perceptual reports are analyzed. We show that INMS and vibrotactile stimulation engage overlapping areas within the topographically appropriate digit representation in the primary somatosensory cortex. Additional brain regions in bilateral secondary somatosensory cortex, premotor cortex, primary motor cortex, insula and posterior parietal cortex, as well as in contralateral prefrontal cortex are also shown to be activated in response to INMS. The combination of INMS and 7T fMRI opens up an unprecedented opportunity to bridge the gap between first-order mechanoreceptive afferent input codes and their spatial, dynamic and perceptual representations in human cortex. DOI:http://dx.doi.org/10.7554/eLife.12812.001 The skin contains multiple types of sensory nerves that inform the brain about events occurring on the surface of the body. One way to study how this process works is to insert a very fine needle through the skin to stimulate a single sensory nerve with a small electrical current. This technique – known as intraneural microstimulation – can activate touch responses in the brain without an object actually contacting the skin. Another technique called functional magnetic resonance imaging (fMRI) has been used to measure brain activity. These studies have revealed that when objects come into contact with the skin of the fingers, they stimulate several sensory nerves at the same time, which results in brain activity in a region called the somatosensory cortex. Sanchez Panchuelo, Ackerley et al. combined fMRI and intraneural microstimulation to map brain activity in response to the activation of individual sensory nerves in the fingers of human volunteers. The experiments show that intraneural stimulation activates many areas of the brain that are also activated by mechanical contact. Future work will use this new method to study the brain's response to signals from different types of sensory nerves. DOI:http://dx.doi.org/10.7554/eLife.12812.002
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Affiliation(s)
- Rosa Maria Sanchez Panchuelo
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
| | - Rochelle Ackerley
- Department of Physiology, University of Gothenburg, Göteborg, Sweden.,Laboratoire de Neurosciences Intégratives et Adaptatives, Aix-Marseille University, Marseille, France
| | - Paul M Glover
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
| | - Richard W Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
| | - Johan Wessberg
- Department of Physiology, University of Gothenburg, Göteborg, Sweden
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
| | - Francis McGlone
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, United Kingdom
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Qi HX, Reed JL, Franca JG, Jain N, Kajikawa Y, Kaas JH. Chronic recordings reveal tactile stimuli can suppress spontaneous activity of neurons in somatosensory cortex of awake and anesthetized primates. J Neurophysiol 2016; 115:2105-23. [PMID: 26912593 DOI: 10.1152/jn.00634.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 02/19/2016] [Indexed: 01/05/2023] Open
Abstract
In somatosensory cortex, tactile stimulation within the neuronal receptive field (RF) typically evokes a transient excitatory response with or without postexcitatory inhibition. Here, we describe neuronal responses in which stimulation on the hand is followed by suppression of the ongoing discharge. With the use of 16-channel microelectrode arrays implanted in the hand representation of primary somatosensory cortex of New World monkeys and prosimian galagos, we recorded neuronal responses from single units and neuron clusters. In 66% of our sample, neuron activity tended to display suppression of firing when regions of skin outside of the excitatory RF were stimulated. In a small proportion of neurons, single-site indentations suppressed firing without initial increases in response to any of the tested sites on the hand. Latencies of suppressive responses to skin indentation (usually 12-34 ms) were similar to excitatory response latencies. The duration of inhibition varied across neurons. Although most observations were from anesthetized animals, we also found similar neuron response properties in one awake galago. Notably, suppression of ongoing neuronal activity did not require conditioning stimuli or multi-site stimulation. The suppressive effects were generally seen following single-site skin indentations outside of the neuron's minimal RF and typically on different digits and palm pads, which have not often been studied in this context. Overall, the characteristics of widespread suppressive or inhibitory response properties with and without initial facilitative or excitatory responses add to the growing evidence that neurons in primary somatosensory cortex provide essential processing for integrating sensory stimulation from across the hand.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Joao G Franca
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Neeraj Jain
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Yoshinao Kajikawa
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
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9
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Ashaber M, Pálfi E, Friedman RM, Palmer C, Jákli B, Chen LM, Kántor O, Roe AW, Négyessy L. Connectivity of somatosensory cortical area 1 forms an anatomical substrate for the emergence of multifinger receptive fields and complex feature selectivity in the squirrel monkey (Saimiri sciureus). J Comp Neurol 2014; 522:1769-85. [PMID: 24214200 DOI: 10.1002/cne.23499] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 11/08/2022]
Abstract
Converging evidence shows that interaction of digit-specific input, which is required to form global tactile percepts, begins as early as area 3b in the primary somatosensory cortex with the involvement of intrinsic lateral connections. How tactile processing is further elaborated in area 1, the next stage of the somatosensory cortical hierarchy, is less understood. This question was investigated by studying the tangential distribution of intrinsic and interareal connections of finger representations of area 1. Retrogradely labeled cell densities and anterogradely labeled fibers and terminal patches were plotted and quantified with respect to the hand representation by combining tract tracing with electrophysiological mapping and intrinsic signal optical imaging in somatosensory areas. Intrinsic connections of distal finger pad representations of area 1 spanned the representation of multiple digits indicating strong cross-digit connectivity. Area 1 distal finger pad regions also established high-density connections with homotopic regions of areas 3b and 2. Although similar to area 3b, connections of area 1 distributed more widely and covered a larger somatotopic representation including more proximal parts of the finger representations. The lateral connectivity pattern of area 1 is a suitable anatomical substrate of the emergence of multifinger receptive fields, complex feature selectivity, and invariant stimulus properties of the neurons.
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Affiliation(s)
- Mária Ashaber
- Complex Systems and Computational Neuroscience Group, Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest, H-1121, Hungary; Department of Anatomy, Histology, and Embryology, Semmelweis University Medical School, Budapest, H-1094, Hungary
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10
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Cortical neuron response properties are related to lesion extent and behavioral recovery after sensory loss from spinal cord injury in monkeys. J Neurosci 2014; 34:4345-63. [PMID: 24647955 DOI: 10.1523/jneurosci.4954-13.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Lesions of the dorsal columns at a mid-cervical level render the hand representation of the contralateral primary somatosensory cortex (area 3b) unresponsive. Over weeks of recovery, most of this cortex becomes responsive to touch on the hand. Determining functional properties of neurons within the hand representation is critical to understanding the neural basis of this adaptive plasticity. Here, we recorded neural activity across the hand representation of area 3b with a 100-electrode array and compared results from owl monkeys and squirrel monkeys 5-10 weeks after lesions with controls. Even after extensive lesions, performance on reach-to-grasp tasks returned to prelesion levels, and hand touches activated territories mainly within expected cortical locations. However, some digit representations were abnormal, such that receptive fields of presumably reactivated neurons were larger and more often involved discontinuous parts of the hand compared with controls. Hand stimulation evoked similar neuronal firing rates in lesion and control monkeys. By assessing the same monkeys with multiple measures, we determined that properties of neurons in area 3b were highly correlated with both the lesion severity and the impairment of hand use. We propose that the reactivation of neurons with near-normal response properties and the recovery of near-normal somatotopy likely supported the recovery of hand use. Given the near-completeness of the more extensive dorsal column lesions we studied, we suggest that alternate spinal afferents, in addition to the few spared primary axon afferents in the dorsal columns, likely have a major role in the reactivation pattern and return of function.
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11
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Négyessy L, Pálfi E, Ashaber M, Palmer C, Jákli B, Friedman RM, Chen LM, Roe AW. Intrinsic horizontal connections process global tactile features in the primary somatosensory cortex: neuroanatomical evidence. J Comp Neurol 2014; 521:2798-817. [PMID: 23436325 DOI: 10.1002/cne.23317] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/31/2013] [Accepted: 02/05/2013] [Indexed: 11/05/2022]
Abstract
To understand manual tactile functions in primates, it is essential to explore the interactions between the finger pad representations in somatosensory cortex. To this end, we used optical imaging and electrophysiological mapping to guide neuroanatomical tracer injections into distal digit tip representations of Brodmann area 3b in the squirrel monkey. Retrogradely labeled cell densities and anterogradely labeled fibers and terminal patches in somatosensory areas were plotted and quantified with respect to tangential distribution. Within area 3b, reciprocal patchy distribution of anterograde and retrograde labeling spanned the representation of the distal pad of multiple digits, indicating strong cross-digit connectivity. Inter-areal connections revealed bundles of long-range fibers projecting anteroposteriorly, connecting area 3b with clusters of labeled neurons and terminal axon arborizations in area 1. Inter-areal linkage appeared to be largely confined to the representation of the injected finger. These findings provide the neuroanatomical basis for the interaction between distal finger pad representations observed by recent electrophysiological studies. We propose that intra-areal connectivity may be heavily involved in interdigit integration such as shape discrimination, whereas long-range inter-areal connections may subserve active touch in a digit-specific manner.
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Affiliation(s)
- László Négyessy
- Department of Theory, Institute for Particle and Nuclear Physics, Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest H-1121, Hungary.
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Vierck CJ, Whitsel BL, Favorov OV, Brown AW, Tommerdahl M. Role of primary somatosensory cortex in the coding of pain. Pain 2013; 154:334-344. [PMID: 23245864 PMCID: PMC4501501 DOI: 10.1016/j.pain.2012.10.021] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 09/15/2012] [Accepted: 10/29/2012] [Indexed: 02/04/2023]
Abstract
The intensity and submodality of pain are widely attributed to stimulus encoding by peripheral and subcortical spinal/trigeminal portions of the somatosensory nervous system. Consistent with this interpretation are studies of surgically anesthetized animals, demonstrating that relationships between nociceptive stimulation and activation of neurons are similar at subcortical levels of somatosensory projection and within the primary somatosensory cortex (in cytoarchitectural areas 3b and 1 of somatosensory cortex, SI). Such findings have led to characterizations of SI as a network that preserves, rather than transforms, the excitatory drive it receives from subcortical levels. Inconsistent with this perspective are images and neurophysiological recordings of SI neurons in lightly anesthetized primates. These studies demonstrate that an extreme anterior position within SI (area 3a) receives input originating predominantly from unmyelinated nociceptors, distinguishing it from posterior SI (areas 3b and 1), long recognized as receiving input predominantly from myelinated afferents, including nociceptors. Of particular importance, interactions between these subregions during maintained nociceptive stimulation are accompanied by an altered SI response to myelinated and unmyelinated nociceptors. A revised view of pain coding within SI cortex is discussed, and potentially significant clinical implications are emphasized.
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Affiliation(s)
- Charles J Vierck
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610-0244, USA Department of Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA Department of Computer Sciences, University of North Carolina School of Medicine, Chapel Hill, NC, USA Senior School, Shadyside Academy, Pittsburgh, PA, USA
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13
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Reed JL, Pouget P, Qi HX, Zhou Z, Bernard MR, Burish MJ, Kaas JH. Effects of spatiotemporal stimulus properties on spike timing correlations in owl monkey primary somatosensory cortex. J Neurophysiol 2012; 108:3353-69. [PMID: 23019003 DOI: 10.1152/jn.00414.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The correlated discharges of cortical neurons in primary somatosensory cortex are a potential source of information about somatosensory stimuli. One aspect of neuronal correlations that has not been well studied is how the spatiotemporal properties of tactile stimuli affect the presence and magnitude of correlations. We presented single- and dual-point stimuli with varying spatiotemporal relationships to the hands of three anesthetized owl monkeys and recorded neuronal activity from 100-electrode arrays implanted in primary somatosensory cortex. Correlation magnitudes derived from joint peristimulus time histogram (JPSTH) analysis of single neuron pairs were used to determine the level of spike timing correlations under selected spatiotemporal stimulus conditions. Correlated activities between neuron pairs were commonly observed, and the proportions of correlated pairs tended to decrease with distance between the recorded neurons. Distance between stimulus sites also affected correlations. When stimuli were presented simultaneously at two sites, ∼37% of the recorded neuron pairs showed significant correlations when adjacent phalanges were stimulated, and ∼21% of the pairs were significantly correlated when nonadjacent digits were stimulated. Spatial proximity of paired stimuli also increased the average correlation magnitude. Stimulus onset asynchronies in the paired stimuli had small effects on the correlation magnitude. These results show that correlated discharges between neurons at the first level of cortical processing provide information about the relative locations of two stimuli on the hand.
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Affiliation(s)
- Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
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14
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Lee J, Woo J, Favorov OV, Tommerdahl M, Lee CJ, Whitsel BL. Columnar distribution of activity dependent gabaergic depolarization in sensorimotor cortical neurons. Mol Brain 2012; 5:33. [PMID: 23006518 PMCID: PMC3520830 DOI: 10.1186/1756-6606-5-33] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 09/11/2012] [Indexed: 11/10/2022] Open
Abstract
Background GABA, the major inhibitory neurotransmitter in CNS, has been demonstrated to paradoxically produce excitation even in mature brain. However activity-dependent form of GABA excitation in cortical neurons has not been observed. Here we report that after an intense electrical stimulation adult cortical neurons displayed a transient GABA excitation that lasted for about 30s. Results Whole-cell patch recordings were performed to evaluate the effects of briefly applied GABA on pyramidal neurons in adult rodent sensorimotor cortical slice before and after 1 s, 20 Hz suprathreshold electrical stimulation of the junction between layer 6 and the underlying white matter (L6/WM stimulation). Immediately after L6/WM stimulation, GABA puffs produced neuronal depolarization in the center of the column-shaped region. However, both prior to or 30s after stimulation GABA puffs produced hyperpolarization of neurons. 2-photon imaging in neurons infected with adenovirus carrying a chloride sensor Clomeleon revealed that GABA induced depolarization is due to an increase in [Cl-]i after stimulation. To reveal the spatial extent of excitatory action of GABA, isoguvacine, a GABAA receptors agonist, was applied right after stimulation while monitoring the intracellular Ca2+ concentration in pyramidal neurons. Isoguvacine induced an increase in [Ca2+]i in pyramidal neurons especially in the center of the column but not in the peripheral regions of the column. The global pattern of the Ca2+ signal showed a column-shaped distribution along the stimulation site. Conclusion These results demonstrate that the well-known inhibitory transmitter GABA rapidly switches from hyperpolarization to depolarization upon synaptic activity in adult somatosensory cortical neurons.
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Affiliation(s)
- Jaekwang Lee
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, CB#7575, Chapel Hill, NC, USA
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