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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.
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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
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2
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Bono D, Belyk M, Longo MR, Dick F. Beyond language: The unspoken sensory-motor representation of the tongue in non-primates, non-human and human primates. Neurosci Biobehav Rev 2022; 139:104730. [PMID: 35691470 DOI: 10.1016/j.neubiorev.2022.104730] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/06/2022] [Accepted: 06/06/2022] [Indexed: 11/28/2022]
Abstract
The English idiom "on the tip of my tongue" commonly acknowledges that something is known, but it cannot be immediately brought to mind. This phrase accurately describes sensorimotor functions of the tongue, which are fundamental for many tongue-related behaviors (e.g., speech), but often neglected by scientific research. Here, we review a wide range of studies conducted on non-primates, non-human and human primates with the aim of providing a comprehensive description of the cortical representation of the tongue's somatosensory inputs and motor outputs across different phylogenetic domains. First, we summarize how the properties of passive non-noxious mechanical stimuli are encoded in the putative somatosensory tongue area, which has a conserved location in the ventral portion of the somatosensory cortex across mammals. Second, we review how complex self-generated actions involving the tongue are represented in more anterior regions of the putative somato-motor tongue area. Finally, we describe multisensory response properties of the primate and non-primate tongue area by also defining how the cytoarchitecture of this area is affected by experience and deafferentation.
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Affiliation(s)
- Davide Bono
- Birkbeck/UCL Centre for Neuroimaging, 26 Bedford Way, London WC1H0AP, UK; Department of Experimental Psychology, UCL Division of Psychology and Language Sciences, 26 Bedford Way, London WC1H0AP, UK.
| | - Michel Belyk
- Department of Speech, Hearing, and Phonetic Sciences, UCL Division of Psychology and Language Sciences, 2 Wakefield Street, London WC1N 1PJ, UK
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck College, University of London, Malet St, London WC1E7HX, UK
| | - Frederic Dick
- Birkbeck/UCL Centre for Neuroimaging, 26 Bedford Way, London WC1H0AP, UK; Department of Experimental Psychology, UCL Division of Psychology and Language Sciences, 26 Bedford Way, London WC1H0AP, UK; Department of Psychological Sciences, Birkbeck College, University of London, Malet St, London WC1E7HX, UK.
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3
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Wang Q, Liao C, Stepniewska I, Gabi M, Kaas JH. Cortical connections of the functional domain for climbing or running in posterior parietal cortex of galagos. J Comp Neurol 2021; 529:2789-2812. [PMID: 33550608 PMCID: PMC9885969 DOI: 10.1002/cne.25123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 02/01/2023]
Abstract
Previous studies in prosimian galagos (Otolemur garnetti) have demonstrated that posterior parietal cortex (PPC) is subdivided into several functionally distinct domains, each of which mediates a specific type of complex movements (e.g., reaching, grasping, hand-to-mouth) and has a different pattern of cortical connections. Here we identified a medially located domain in PPC where combined forelimb and hindlimb movements, as if climbing or running, were evoked by long-train intracortical microstimulation. We injected anatomical tracers in this climbing/running domain of PPC to reveal its cortical connections. Our results showed the PPC climbing domain had dense intrinsic connections within rostral PPC and reciprocal connections with forelimb and hindlimb region in primary motor cortex (M1) of the ipsilateral hemisphere. Fewer connections were with dorsal premotor cortex (PMd), supplementary motor (SMA), and cingulate motor (CMA) areas, as well as somatosensory cortex including areas 3a, 3b, and 1-2, secondary somatosensory (S2), parietal ventral (PV), and retroinsular (Ri) areas. The rostral portion of the climbing domain had more connections with primary somatosensory cortex than the caudal portion. Cortical projections were found in functionally matched domains in M1 and premotor cortex (PMC). Similar patterns of connections with fewer labeled neurons and terminals were seen in the contralateral hemisphere. These connection patterns are consistent with the proposed role of the climbing/running domain as part of a parietal-frontal network for combined use of the limbs in locomotion as in climbing and running. The cortical connections identify this action-specific domain in PPC as a more somatosensory driven domain.
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Affiliation(s)
- Qimeng Wang
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Chia‐Chi Liao
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Iwona Stepniewska
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Mariana Gabi
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Jon H. Kaas
- Department of Psychology Vanderbilt University Nashville Tennessee USA
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Sörös P, Schäfer S, Witt K. Model-Based and Model-Free Analyses of the Neural Correlates of Tongue Movements. Front Neurosci 2020; 14:226. [PMID: 32265635 PMCID: PMC7105808 DOI: 10.3389/fnins.2020.00226] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 03/02/2020] [Indexed: 12/11/2022] Open
Abstract
The tongue performs movements in all directions to subserve its diverse functions in chewing, swallowing, and speech production. Using task-based functional MRI in a group of 17 healthy young participants, we studied (1) potential differences in the cerebral control of frontal (protrusion), horizontal (side to side), and vertical (elevation) tongue movements and (2) inter-individual differences in tongue motor control. To investigate differences between different tongue movements, we performed voxel-wise multiple linear regressions. To investigate inter-individual differences, we applied a novel approach, spatio-temporal filtering of independent components. For this approach, individual functional data were decomposed into spatially independent components and corresponding time courses using independent component analysis. A temporal filter (correlation with the expected brain response) was used to identify independent components time-locked to the tongue motor tasks. A spatial filter (cross-correlation with established neurofunctional systems) was used to identify brain activity not time-locked to the tasks. Our results confirm the importance of an extended bilateral cortical and subcortical network for the control of tongue movements. Frontal (protrusion) tongue movements, highly overlearned movements related to speech production, showed less activity in the frontal and parietal lobes compared to horizontal (side to side) and vertical (elevation) movements and greater activity in the left frontal and temporal lobes compared to vertical movements (cluster-forming threshold of Z > 3.1, cluster significance threshold of p < 0.01, corrected for multiple comparisons). The investigation of inter-individual differences revealed a component representing the tongue primary sensorimotor cortex time-locked to the task in all participants. Using the spatial filter, we found the default mode network in 16 of 17 participants, the left fronto-parietal network in 16, the right fronto-parietal network in 8, and the executive control network in four participants (Pearson's r > 0.4 between neurofunctional systems and individual components). These results demonstrate that spatio-temporal filtering of independent components allows to identify individual brain activity related to a specific task and also structured spatiotemporal processes representing known neurofunctional systems on an individual basis. This novel approach may be useful for the assessment of individual patients and results may be related to individual clinical, behavioral, and genetic information.
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Affiliation(s)
- Peter Sörös
- Neurology, School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Sarah Schäfer
- Neurology, School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Karsten Witt
- Neurology, School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
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Sessle BJ. Can you be too old for oral implants? An update on ageing and plasticity in the oro‐facial sensorimotor system. J Oral Rehabil 2019; 46:936-951. [DOI: 10.1111/joor.12830] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 05/06/2019] [Accepted: 05/26/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Barry J. Sessle
- Faculty of Dentistry University of Toronto Toronto Ontario Canada
- Department of Physiology, Faculty of Medicine University of Toronto Toronto Ontario Canada
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6
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Mălîia MD, Donos C, Barborica A, Popa I, Ciurea J, Cinatti S, Mîndruţă I. Functional mapping and effective connectivity of the human operculum. Cortex 2018; 109:303-321. [PMID: 30414541 DOI: 10.1016/j.cortex.2018.08.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 05/05/2018] [Accepted: 08/27/2018] [Indexed: 11/30/2022]
Abstract
The operculum, defined as the cortex adjacent to the insula, is a large structure encompassing three lobes, with a recognized role in a variety of neurologic and psychiatric conditions. Its complex functions include sensory, motor, autonomic and cognitive processing. In humans, these are extended with the addition of language. These functions are implemented by highly specialized neuronal populations and their widespread connections, which our study aims at mapping in detail. We studied a group of 31 patients that were explored with intracranial electrodes during the pre-surgical workup for drug-resistant epilepsy. We have selected the subset of contacts implanted in non-epileptogenic opercular cortex and we analyzed the neurophysiological and behavioral responses to direct electrical stimulation. The functional mapping was performed by applying 1 Hz and 50 Hz electrical stimulation on 252 contact pairs and recording the threshold for evoking clinical effects. The effective connectivity was assessed using cortico-cortical evoked potentials elicited by single-pulse electrical stimulation in a subset of 19 patients. The locations of the effects grouped in twelve distinct semiological classes were analyzed. The most frequent effects evoked by stimulation of the frontal operculum were language related (29%). The Rolandic area produced most often oropharyngeal symptoms (47%), the parietal operculum produced somatosensory effects (67%), while the temporal evoked auditory (58%) semiology. The connectivity pattern was complex, with these structures having widespread ipsilateral and contralateral projections. The local connections between the opercular subregions and with the insula, as well as with more distant areas like the cingulate gyrus, were distinguished by strength and between-subjects consistency. In conclusion, we demonstrate specific opercular functionality, distinct from the one of the insular cortex. The study is complemented by a literature review on the opercular functional connectome in human and non-human primates.
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Affiliation(s)
- Mihai-Dragoş Mălîia
- Neurology Department, University Emergency Hospital, Bucharest, Romania; Physics Department, University of Bucharest, Bucharest, Romania
| | - Cristian Donos
- Physics Department, University of Bucharest, Bucharest, Romania
| | - Andrei Barborica
- Physics Department, University of Bucharest, Bucharest, Romania; FHC Inc., Bowdoin, ME, USA
| | - Irina Popa
- Neurology Department, University Emergency Hospital, Bucharest, Romania; Neurology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Jean Ciurea
- Neurosurgery Department, Bagdasar-Arseni Hospital, Bucharest, Romania
| | - Sandra Cinatti
- Neurology Department, University Emergency Hospital, Bucharest, Romania
| | - Ioana Mîndruţă
- Neurology Department, University Emergency Hospital, Bucharest, Romania; Neurology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
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Lin CS. Meta-analysis of brain mechanisms of chewing and clenching movements. J Oral Rehabil 2018; 45:627-639. [DOI: 10.1111/joor.12657] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2018] [Indexed: 12/26/2022]
Affiliation(s)
- C-S. Lin
- Department of Dentistry; School of Dentistry; National Yang-Ming University; Taipei Taiwan
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Saraf MP, Balaram P, Pifferi F, Gămănuţ R, Kennedy H, Kaas JH. Architectonic features and relative locations of primary sensory and related areas of neocortex in mouse lemurs. J Comp Neurol 2018; 527:625-639. [PMID: 29484648 DOI: 10.1002/cne.24419] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/08/2018] [Accepted: 02/08/2018] [Indexed: 12/27/2022]
Abstract
Mouse lemurs are the smallest of the living primates, and are members of the understudied radiation of strepsirrhine lemurs of Madagascar. They are thought to closely resemble the ancestral primates that gave rise to present day primates. Here we have used multiple histological and immunochemical methods to identify and characterize sensory areas of neocortex in four brains of adult lemurs obtained from a licensed breeding colony. We describe the laminar features for the primary visual area (V1), the secondary visual area (V2), the middle temporal visual area (MT) and area prostriata, somatosensory areas S1(3b), 3a, and area 1, the primary motor cortex (M1), and the primary auditory cortex (A1). V1 has "blobs" with "nonblob" surrounds, providing further evidence that this type of modular organization might have evolved early in the primate lineage to be retained in all extant primates. The laminar organization of V1 further supports the view that sublayers of layer 3 of primates have been commonly misidentified as sublayers of layer 4. S1 (area 3b) is proportionately wider than the elongated area observed in anthropoid primates, and has disruptions that may distinguish representations of the hand, face, teeth, and tongue. Primary auditory cortex is located in the upper temporal cortex and may include a rostral area, R, in addition to A1. The resulting architectonic maps of cortical areas in mouse lemurs can usefully guide future studies of cortical connectivity and function.
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Affiliation(s)
- Mansi P Saraf
- Department of Psychology, Vanderbilt University, Nashville, TN, 37240
| | - Pooja Balaram
- Department of Psychology, Vanderbilt University, Nashville, TN, 37240.,MECADEV UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, Brunoy, 91800, France
| | - Fabien Pifferi
- Université de Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, 69500, France
| | - Răzvan Gămănuţ
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Chinese Academy of Science (CAS) Key Laboratory of Primate Neurobiology, CAS, Shanghai, 200031, China
| | - Henry Kennedy
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Chinese Academy of Science (CAS) Key Laboratory of Primate Neurobiology, CAS, Shanghai, 200031, China
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN, 37240
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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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Prinster A, Cantone E, Verlezza V, Magliulo M, Sarnelli G, Iengo M, Cuomo R, Di Salle F, Esposito F. Cortical representation of different taste modalities on the gustatory cortex: A pilot study. PLoS One 2017; 12:e0190164. [PMID: 29281722 PMCID: PMC5744997 DOI: 10.1371/journal.pone.0190164] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 12/08/2017] [Indexed: 12/22/2022] Open
Abstract
Background Right insular cortex is involved in taste discrimination, but its functional organization is still poorly known. In general, sensory cortices represent the spatial prevalence of relevant features for each sensory modality (visual, auditory, somatosensory) in an ordered way across the cortical space. Following this analogy, we hypothesized that primary taste cortex is organized in similar ordered way in response to six tastes with known receptorial mechanisms (sweet, bitter, sour, salt, umami, CO2). Design Ten normal subjects were enrolled in a pilot study. We used functional magnetic resonance imaging (fMRI), a high resolution cortical registration method, and specialized procedures of feature prevalence localization, to map fMRI responses within the right insular cortex, to water solutions of quinine hydrochloride (bitter), Acesulfamate K (sweet), sodium chloride (salt), mono potassium glutamate + inosine 5' mono phosphate (Umami), citric acid (sour) and carbonated water (CO2). During an fMRI scan delivery of the solutions was applied in pseudo-random order interleaved with cleaning water. Results Two subjects were discarded due to excessive head movements. In the remaining subjects, statistically significant activations were detected in the fMRI responses to all tastes in the right insular cortex (p<0.05, family-wise corrected for multiple comparisons). Cortical representation of taste prevalence highlighted two spatially segregated clusters, processing two and three tastes coupled together (sweet-bitter and salt-umami-sour), with CO2 in between. Conclusions Cortical representation of taste prevalence within the right primary taste cortex appears to follow the ecological purpose of enhancing the discrimination between safe nutrients and harmful substances.
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Affiliation(s)
- Anna Prinster
- Biostructure and Bioimaging Institute, National Research Council, Naples, Italy
- * E-mail:
| | - Elena Cantone
- Section of ENT, Department of Neuroscience, "Federico II" University, Naples, Italy
| | - Viviana Verlezza
- Gastroenterology Unit, Department of Clinical and Experimental Medicine, “Federico II” University, Naples, Italy
| | - Mario Magliulo
- Biostructure and Bioimaging Institute, National Research Council, Naples, Italy
| | - Giovanni Sarnelli
- Gastroenterology Unit, Department of Clinical and Experimental Medicine, “Federico II” University, Naples, Italy
| | - Maurizio Iengo
- Section of ENT, Department of Neuroscience, "Federico II" University, Naples, Italy
| | - Rosario Cuomo
- Gastroenterology Unit, Department of Clinical and Experimental Medicine, “Federico II” University, Naples, Italy
| | - Francesco Di Salle
- Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi (Salerno), Italy
| | - Fabrizio Esposito
- Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi (Salerno), Italy
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11
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Avivi-Arber L, Sessle BJ. Jaw sensorimotor control in healthy adults and effects of ageing. J Oral Rehabil 2017; 45:50-80. [DOI: 10.1111/joor.12554] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2017] [Indexed: 12/22/2022]
Affiliation(s)
- L. Avivi-Arber
- Faculty of Dentistry; University of Toronto; Toronto ON Canada
| | - B. J. Sessle
- Faculty of Dentistry; University of Toronto; Toronto ON Canada
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12
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Avivi-Arber L, Lee JC, Sood M, Lakschevitz F, Fung M, Barashi-Gozal M, Glogauer M, Sessle BJ. Long-term neuroplasticity of the face primary motor cortex and adjacent somatosensory cortex induced by tooth loss can be reversed following dental implant replacement in rats. J Comp Neurol 2015; 523:2372-89. [DOI: 10.1002/cne.23793] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 04/10/2015] [Accepted: 04/15/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Limor Avivi-Arber
- Department of Prosthodontic; Faculty of Dentistry; University of Toronto; Ontario Canada
- Department of Oral Physiology; Faculty of Dentistry; University of Toronto; Ontario Canada
| | - Jye-Chang Lee
- Department of Oral Physiology; Faculty of Dentistry; University of Toronto; Ontario Canada
| | - Mandeep Sood
- Department of Oral Physiology; Faculty of Dentistry; University of Toronto; Ontario Canada
- Department of Orthodontics; Faculty of Dentistry; University of Toronto; Ontario Canada
| | - Flavia Lakschevitz
- Department of Periodontics; Faculty of Dentistry; University of Toronto; Ontario Canada
| | - Michelle Fung
- Department of Oral Physiology; Faculty of Dentistry; University of Toronto; Ontario Canada
| | - Maayan Barashi-Gozal
- Department of Periodontics; Faculty of Dentistry; University of Toronto; Ontario Canada
| | - Michael Glogauer
- Department of Periodontics; Faculty of Dentistry; University of Toronto; Ontario Canada
| | - Barry J. Sessle
- Department of Oral Physiology; Faculty of Dentistry; University of Toronto; Ontario Canada
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13
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Oral somatosensory awareness. Neurosci Biobehav Rev 2014; 47:469-84. [DOI: 10.1016/j.neubiorev.2014.09.015] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 09/03/2014] [Accepted: 09/10/2014] [Indexed: 12/19/2022]
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Cerkevich CM, Qi HX, Kaas JH. Corticocortical projections to representations of the teeth, tongue, and face in somatosensory area 3b of macaques. J Comp Neurol 2014; 522:546-72. [PMID: 23853118 DOI: 10.1002/cne.23426] [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: 05/27/2013] [Revised: 06/24/2013] [Accepted: 07/03/2013] [Indexed: 01/14/2023]
Abstract
We placed injections of anatomical tracers into representations of the tongue, teeth, and face in the primary somatosensory cortex (area 3b) of macaque monkeys. Our injections revealed strong projections to representations of the tongue and teeth from other parts of the oral cavity responsive region in 3b. The 3b face also provided input to the representations of the intraoral structures. The primary representation of the face showed a pattern of intrinsic connections similar to that of the mouth. The area 3b hand representation provided little to no input to either the mouth or the face representations. The mouth and face representations of area 3b received projections from the presumptive oral cavity and face regions of other somatosensory areas in the anterior parietal cortex and the lateral sulcus, including areas 3a, 1, 2, the second somatosensory area (S2), the parietal ventral area (PV), and cortex that may include the parietal rostral (PR) and ventral somatosensory (VS) areas. Additional inputs came from primary motor (M1) and ventral premotor (PMv) areas. This areal pattern of projections is similar to the well-studied pattern revealed by tracer injections in regions of 3b representing the hand. The tongue representation appeared to be unique in area 3b in that it also received inputs from areas in the anterior upper bank of the lateral sulcus and anterior insula that may include the primary gustatory area (area G) and other cortical taste-processing areas, as well as a region of lateral prefrontal cortex (LPFC) lining the principal sulcus.
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Cerkevich CM, Qi HX, Kaas JH. Thalamic input to representations of the teeth, tongue, and face in somatosensory area 3b of macaque monkeys. J Comp Neurol 2014; 521:3954-71. [PMID: 23873330 DOI: 10.1002/cne.23386] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 05/17/2013] [Accepted: 06/07/2013] [Indexed: 12/18/2022]
Abstract
Representations of the parts of the oral cavity and face in somatosensory area 3b of macaque monkeys were identified with microelectrode recordings and injected with different neuroanatomical tracers to reveal patterns of thalamic projections to tongue, teeth, and other representations in primary somatosensory cortex. The locations of injection sites and resulting labeled neurons were further determined by relating sections processed to reveal tracers to those processed for myeloarchitecture in the cortex and multiple architectural stains in the thalamus. The ventroposterior medial subnucleus (VPM) for touch was identified as separate from the ventroposterior medial parvicellular nucleus (VPMpc) for taste by differential expression of several types of proteins. Our results revealed somatotopically matched projections from VPM to the part of 3b representing intra-oral structures and the face. Retrogradely labeled cells resulting from injections in area 3b were also found in other thalamic nuclei including: anterior pulvinar (Pa), ventroposterior inferior (VPI), ventroposterior superior (VPS), ventroposterior lateral (VPL), ventral lateral (VL), center median (CM), central lateral (CL), and medial dorsal (MD). None of our injections, including those into the representation of the tongue, labeled neurons in VPMpc, the thalamic taste nucleus. Thus, area 3b does not appear to be involved in processing taste information from the thalamus. This result stands in contrast to those reported for New World monkeys.
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Qi HX, Kaas JH, Reed JL. The reactivation of somatosensory cortex and behavioral recovery after sensory loss in mature primates. Front Syst Neurosci 2014; 8:84. [PMID: 24860443 PMCID: PMC4026759 DOI: 10.3389/fnsys.2014.00084] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 04/22/2014] [Indexed: 02/04/2023] Open
Abstract
In our experiments, we removed a major source of activation of somatosensory cortex in mature monkeys by unilaterally sectioning the sensory afferents in the dorsal columns of the spinal cord at a high cervical level. At this level, the ascending branches of tactile afferents from the hand are cut, while other branches of these afferents remain intact to terminate on neurons in the dorsal horn of the spinal cord. Immediately after such a lesion, the monkeys seem relatively unimpaired in locomotion and often use the forelimb, but further inspection reveals that they prefer to use the unaffected hand in reaching for food. In addition, systematic testing indicates that they make more errors in retrieving pieces of food, and start using visual inspection of the rotated hand to confirm the success of the grasping of the food. Such difficulties are not surprising as a complete dorsal column lesion totally deactivates the contralateral hand representation in primary somatosensory cortex (area 3b). However, hand use rapidly improves over the first post-lesion weeks, and much of the hand representational territory in contralateral area 3b is reactivated by inputs from the hand in roughly a normal somatotopic pattern. Quantitative measures of single neuron response properties reveal that reactivated neurons respond to tactile stimulation on the hand with high firing rates and only slightly longer latencies. We conclude that preserved dorsal column afferents after nearly complete lesions contribute to the reactivation of cortex and the recovery of the behavior, but second-order sensory pathways in the spinal cord may also play an important role. Our microelectrode recordings indicate that these preserved first-order, and second-order pathways are initially weak and largely ineffective in activating cortex, but they are potentiated during the recovery process. Therapies that would promote this potentiation could usefully enhance recovery after spinal cord injury.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University Nashville, TN, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University Nashville, TN, USA
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University Nashville, TN, USA
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Sarko DK, Leitch DB, Catania KC. Cutaneous and periodontal inputs to the cerebellum of the naked mole-rat (Heterocephalus glaber). Front Neuroanat 2013; 7:39. [PMID: 24302898 PMCID: PMC3831171 DOI: 10.3389/fnana.2013.00039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 10/25/2013] [Indexed: 11/20/2022] Open
Abstract
The naked mole-rat (Heterocephalus glaber) is a small fossorial rodent with specialized dentition that is reflected by the large cortical area dedicated to representation of the prominent incisors. Due to naked mole-rats’ behavioral reliance on the incisors for digging and for manipulating objects, as well as their ability to move the lower incisors independently, we hypothesized that expanded somatosensory representations of the incisors would be present within the cerebellum in order to accommodate a greater degree of proprioceptive, cutaneous, and periodontal input. Multiunit electrophysiological recordings targeting the ansiform lobule were used to investigate tactile inputs from receptive fields on the entire body with a focus on the incisors. Similar to other rodents, a fractured somatotopy appeared to be present with discrete representations of the same receptive fields repeated within each folium of the cerebellum. These findings confirm the presence of somatosensory inputs to a large area of the naked mole-rat cerebellum with particularly extensive representations of the lower incisors and mystacial vibrissae. We speculate that these extensive inputs facilitate processing of tactile cues as part of a sensorimotor integration network that optimizes how sensory stimuli are acquired through active exploration and in turn adjusts motor outputs (such as independent movement of the lower incisors). These results highlight the diverse sensory specializations and corresponding brain organizational schemes that have evolved in different mammals to facilitate exploration of and interaction with their environment.
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Affiliation(s)
- Diana K Sarko
- Department of Anatomy, Cell Biology and Physiology, Edward Via College of Osteopathic Medicine Spartanburg, SC, USA
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Grabenhorst F, Rolls ET. The representation of oral fat texture in the human somatosensory cortex. Hum Brain Mapp 2013; 35:2521-30. [PMID: 24038614 DOI: 10.1002/hbm.22346] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 04/24/2013] [Accepted: 05/28/2013] [Indexed: 11/11/2022] Open
Abstract
How fat is sensed in the mouth and represented in the brain is important in relation to the pleasantness of food, appetite control, and the design of foods that reproduce the mouthfeel of fat yet have low energy content. We show that the human somatosensory cortex (SSC) is involved in oral fat processing via functional coupling to the orbitofrontal cortex (OFC), where the pleasantness of fat texture is represented. Using functional MRI, we found that activity in SSC was more strongly correlated with the OFC during the consumption of a high fat food with a pleasant (vanilla) flavor compared to a low fat food with the same flavor. This effect was not found in control analyses using high fat foods with a less pleasant flavor or pleasant-flavored low fat foods. SSC activity correlated with subjective ratings of fattiness, but not of texture pleasantness or flavor pleasantness, indicating a representation that is not involved in hedonic processing per se. Across subjects, the magnitude of OFC-SSC coupling explained inter-individual variation in texture pleasantness evaluations. These findings extend known SSC functions to a specific role in the processing of pleasant-flavored oral fat, and identify a neural mechanism potentially important in appetite, overeating, and obesity.
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Affiliation(s)
- Fabian Grabenhorst
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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Leitch DB, Catania KC. Structure, innervation and response properties of integumentary sensory organs in crocodilians. ACTA ACUST UNITED AC 2013; 215:4217-30. [PMID: 23136155 DOI: 10.1242/jeb.076836] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Integumentary sensory organs (ISOs) are densely distributed on the jaws of crocodilians and on body scales of members of the families Crocodilidae and Gavialidae. We examined the distribution, anatomy, innervation and response properties of ISOs on the face and body of crocodilians and documented related behaviors for an alligatorid (Alligator mississippiensis) and a crocodylid (Crocodylus niloticus). Each of the ISOs (roughly 4000 in A. mississippiensis and 9000 in C. niloticus) was innervated by networks of afferents supplying multiple different mechanoreceptors. Electrophysiological recordings from the trigeminal ganglion and peripheral nerves were made to isolate single-unit receptive fields and to test possible osmoreceptive and electroreceptive functions. Multiple small (<0.1 mm(2)) receptive fields, often from a single ISO, were recorded from the premaxilla, the rostral dentary, the gingivae and the distal digits. These responded to a median threshold of 0.08 mN. The less densely innervated caudal margins of the jaws had larger receptive fields (>100 mm(2)) and higher thresholds (13.725 mN). Rapidly adapting, slowly adapting type I and slowly adapting type II responses were identified based on neuronal responses. Several rapidly adapting units responded maximally to vibrations at 20-35 Hz, consistent with reports of the ISOs' role in detecting prey-generated water surface ripples. Despite crocodilians' armored bodies, the ISOs imparted a mechanical sensitivity exceeding that of primate fingertips. We conclude that crocodilian ISOs have diverse functions, including detection of water movements, indicating when to bite based on direct contact of pursued prey, and fine tactile discrimination of items held in the jaws.
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Affiliation(s)
- Duncan B Leitch
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37235, USA
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20
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Abstract
We can learn about the evolution of neocortex in primates through comparative studies of cortical organization in primates and those mammals that are the closest living relatives of primates, in conjunction with brain features revealed by the skull endocasts of fossil archaic primates. Such studies suggest that early primates had acquired a number of features of neocortex that now distinguish modern primates. Most notably, early primates had an array of new visual areas, and those visual areas widely shared with other mammals had been modified. Posterior parietal cortex was greatly expanded with sensorimotor modules for reaching, grasping, and personal defense. Motor cortex had become more specialized for hand use, and the functions of primary motor cortex were enhanced by the addition and development of premotor and cingulate motor areas. Cortical architecture became more varied, and cortical neuron populations became denser overall than in nonprimate ancestors. Primary visual cortex had the densest population of neurons, and this became more pronounced in the anthropoid radiation. Within the primate clade, considerable variability in cortical size, numbers of areas, and architecture evolved.
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Affiliation(s)
- Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN, USA.
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Avivi-Arber L, Martin R, Lee JC, Sessle BJ. Face sensorimotor cortex and its neuroplasticity related to orofacial sensorimotor functions. Arch Oral Biol 2011; 56:1440-65. [DOI: 10.1016/j.archoralbio.2011.04.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 04/05/2011] [Accepted: 04/06/2011] [Indexed: 12/20/2022]
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Avivi-Arber L, Lee JC, Sessle BJ. Face sensorimotor cortex neuroplasticity associated with intraoral alterations. PROGRESS IN BRAIN RESEARCH 2011; 188:135-50. [DOI: 10.1016/b978-0-444-53825-3.00014-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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23
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Sarko DK, Leitch DB, Girard I, Sikes RS, Catania KC. Organization of somatosensory cortex in the Northern grasshopper mouse (Onychomys leucogaster), a predatory rodent. J Comp Neurol 2011; 519:64-74. [PMID: 21120928 PMCID: PMC3064439 DOI: 10.1002/cne.22504] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Northern grasshopper mice (Onychomys leucogaster) are among the most highly carnivorous rodents in North America. Because predatory mammals may have specialization of senses used to detect prey, we investigated the organization of sensory areas within grasshopper mouse neocortex and quantified the number of myelinated axons in grasshopper mouse trigeminal, cochlear, and optic nerves. Multiunit electrophysiological recordings combined with analysis of flattened sections of neocortex processed for cytochrome oxidase were used to determine the topography of primary somatosensory cortex (S1) and the location and size of both the visual and auditory cortex in adult animals. These findings were then related to the distinctive chemoarchitecture of layer IV visible in flattened cortical sections of juvenile grasshopper mice labeled with the serotonin transporter (SERT) antibody, revealing a striking correspondence between electrophysiological maps and cortical anatomy.
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Affiliation(s)
- Diana K Sarko
- Department of Hearing and Speech Sciences, Vanderbilt University, Nashville, Tennessee 37232, USA.
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Trulsson M, Francis ST, Bowtell R, McGlone F. Brain Activations in Response to Vibrotactile Tooth Stimulation: a Psychophysical and fMRI Study. J Neurophysiol 2010; 104:2257-65. [PMID: 20668275 DOI: 10.1152/jn.00565.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The tactile sensitivity of the teeth, and associated periodontium, serves important sensory and motor functions. Microneurographic recordings from human periodontal ligament mechanoreceptor (PDLM) nerves, in response to tooth loading, reveal discharge patterns with sole slowly adapting (SA) II-type characteristics, highlighting the unique role of PDLMs in oral sensory processes. Here we investigate these receptors' properties, psychophysically and with neuroimaging (fMRI), in response to varying frequencies of dynamic (vibrotactile) stimulation. The finding of increased activity in primary (SI) and secondary (SII) somatosensory cortices (SI and SII) at low frequencies of stimulation (20 Hz) as compared with higher frequencies (50 and 100 Hz), shows an increased entrainment of the PDLMs at this lower frequency in line with expected SA II-type response properties. At the highest frequency (100 Hz), no significant activity was found in SI or SII, suggesting this frequency is outside the range of activity of PDLMs. An activation matrix is mapped that includes SI, SII, insular, inferior frontal gyrus, inferior parietal lobe and supplementary motor area as well as middle frontal gyrus and cerebellum. We compared the responses to tooth stimulation with those produced by identical vibrotactile stimulation of the finger. The results strongly suggest that the PDLMs play a significant role in the specification of the forces used to hold and manipulate food between teeth, and in these respects, the masticatory system appears analogous to fine finger-control mechanisms used during precision manipulation of small objects. Because fMRI reveals activations in posterior insular cortex, we also speculate that PDLMs, and SA II-type receptors in general, may be involved in one aspect of the feeling of body ownership.
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Affiliation(s)
- Mats Trulsson
- Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Susan T. Francis
- Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom; and
| | - Richard Bowtell
- Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom; and
| | - Francis McGlone
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, United Kingdom
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Avivi-Arber L, Lee JC, Sessle BJ. Effects of incisor extraction on jaw and tongue motor representations within face sensorimotor cortex of adult rats. J Comp Neurol 2010; 518:1030-45. [DOI: 10.1002/cne.22261] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Laitman JT, Albertine KH. Primates of All Types Swing Through the Pages of The Anatomical Record. Anat Rec (Hoboken) 2010; 293:539-40. [DOI: 10.1002/ar.21149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Burish MJ, Stepniewska I, Kaas JH. Microstimulation and architectonics of frontoparietal cortex in common marmosets (Callithrix jacchus). J Comp Neurol 2008; 507:1151-68. [PMID: 18175349 DOI: 10.1002/cne.21596] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We investigated the organization of frontoparietal cortex in the common marmoset (Callithrix jacchus) by using intracortical microstimulation and an architectonic analysis. Primary motor cortex (M1) was identified as an area that evoked visible movements at low levels of electric current and had a full body representation of the contralateral musculature. Primary motor cortex represented the contralateral body from hindlimb to face in a mediolateral sequence, with individual movements such as jaw and wrist represented in multiple nearby locations. Primary motor cortex was coextensive with an agranular area of cortex marked by a distinct layer V of large pyramidal cells that gradually decreased in size toward the rostral portion of the area and was more homogenous in appearance than other New World primates. In addition to M1, stimulation also evoked movements from several other areas of frontoparietal cortex. Caudal to primary motor cortex, area 3a was identified as a thin strip of cortex where movements could be evoked at thresholds similar to those in M1. Rostral to primary motor cortex, supplementary motor cortex and premotor areas responded to higher stimulation currents and had smaller layer V pyramidal cells. Other areas evoking movements included primary somatosensory cortex (area 3b), two lateral somatosensory areas (areas PV and S2), and a caudal somatosensory area. Our results suggest that frontoparietal cortex in marmosets is organized in a similar fashion to that of other New World primates.
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Affiliation(s)
- Mark J Burish
- Neuroscience Graduate Program and Medical Scientist Training Program, Vanderbilt University, Nashville, Tennessee 37240, USA
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Kaas JH. The evolution of the complex sensory and motor systems of the human brain. Brain Res Bull 2007; 75:384-90. [PMID: 18331903 DOI: 10.1016/j.brainresbull.2007.10.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Accepted: 10/17/2007] [Indexed: 11/25/2022]
Abstract
Inferences about how the complex sensory and motor systems of the human brain evolved are based on the results of comparative studies of brain organization across a range of mammalian species, and evidence from the endocasts of fossil skulls of key extinct species. The endocasts of the skulls of early mammals indicate that they had small brains with little neocortex. Evidence from comparative studies of cortical organization from small-brained mammals of the six major branches of mammalian evolution supports the conclusion that the small neocortex of early mammals was divided into roughly 20-25 cortical areas, including primary and secondary sensory fields. In early primates, vision was the dominant sense, and cortical areas associated with vision in temporal and occipital cortex underwent a significant expansion. Comparative studies indicate that early primates had 10 or more visual areas, and somatosensory areas with expanded representations of the forepaw. Posterior parietal cortex was also expanded, with a caudal half dominated by visual inputs, and a rostral half dominated by somatosensory inputs with outputs to an array of seven or more motor and visuomotor areas of the frontal lobe. Somatosensory areas and posterior parietal cortex became further differentiated in early anthropoid primates. As larger brains evolved in early apes and in our hominin ancestors, the number of cortical areas increased to reach an estimated 200 or so in present day humans, and hemispheric specializations emerged. The large human brain grew primarily by increasing neuron number rather than increasing average neuron size.
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Affiliation(s)
- Jon H Kaas
- Department of Psychology, Vanderbilt University, 301 Wilson Hall, 111 21st Avenue South, Nashville, TN 37203, USA.
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Iyengar S, Qi HX, Jain N, Kaas JH. Cortical and thalamic connections of the representations of the teeth and tongue in somatosensory cortex of new world monkeys. J Comp Neurol 2007; 501:95-120. [PMID: 17206603 DOI: 10.1002/cne.21232] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Connections of representations of the teeth and tongue in primary somatosensory cortex (area 3b) and adjoining cortex were revealed in owl, squirrel, and marmoset monkeys with injections of fluorescent tracers. Injection sites were identified by microelectrode recordings from neurons responsive to touch on the teeth or tongue. Patterns of cortical label were related to myeloarchitecture in sections cut parallel to the surface of flattened cortex, and to coronal sections of the thalamus processed for cytochrome oxidase (CO). Cortical sections revealed a caudorostral series of myelin dense ovals (O1-O4) in area 3b that represent the periodontal receptors of the contralateral teeth, the contralateral tongue, the ipsilateral teeth, and the ipsilateral tongue. The ventroposterior medial subnucleus, VPM, and the ventroposterior medial parvicellular nucleus for taste, VPMpc, were identified in the thalamic sections. Injections placed in the O1 oval representing teeth labeled neurons in VPM, while injections in O2 representing the tongue labeled neurons in both VPMpc and VPM. These injections also labeled adjacent part of areas 3a and 1, and locations in the lateral sulcus and frontal lobe. Callosally, connections of the ovals were most dense with corresponding ovals. Injections in the area 1 representation of the tongue labeled neurons in VPMpc and VPM, and ipsilateral area 3b ovals, area 3a, opercular cortex, and cortex in the lateral sulcus. Contralaterally, labeled neurons were mostly in area 1. The results implicate portions of areas 3b, 3a, and 1 in the processing of tactile information from the teeth and tongue, and possibly taste information from the tongue.
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Affiliation(s)
- Soumya Iyengar
- National Brain Research Centre, Deemed University, 122050, Haryana, India
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