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Bilateral representations of touch in the primary somatosensory cortex

Authors

Luigi

Christoph Braun

Nicholas P. Holmes

Alessandro

Francesco Pavani



Abstract

According to current textbook knowledge, the primary somatosensory cortex (SI) supports unilateral tactile representations, whereas structures beyond SI, in particular the secondary somatosensory cortex (SII), support bilateral tactile representations. However, dexterous and well-coordinated bimanual motor tasks require early integration of bilateral tactile information. Sequential processing, first of unilateral and subsequently of bilateral sensory information, might not be sufficient to accomplish these tasks. This view of sequential processing in the somatosensory system might therefore be questioned, at least for demanding bimanual tasks. Evidence from the last 15 years is forcing a revision of this textbook notion. Studies in animals and humans indicate that SI is more than a simple relay for unilateral sensory information and, together with SII, contributes to the integration of somatosensory inputs from both sides of the body. Here, we review a series of recent works from our own and other laboratories in favour of interactions between tactile stimuli on the two sides of the body at early stages of processing. We focus on tactile processing, although a similar logic may also apply to other aspects of somatosensation. We begin by describing the basic anatomy and physiology of interhemispheric transfer, drawing on neurophysiological studies in animals and behavioural studies in humans that showed tactile interactions between body sides, both in healthy and in brain-damaged individuals. Then we describe the neural substrates of bilateral interactions in somatosensation as revealed by neurophysiological work in animals and neuroimaging studies in humans (i.e., functional magnetic resonance imaging, magnetoencephalography, and transcranial magnetic stimulation). Finally, we conclude with considerations on the dilemma of how efficiently integrating bilateral sensory information at early processing stages can coexist with more lateralized representations of somatosensory input, in the context of motor control.

Citation

Tamè, L., Braun, C., Holmes, N. P., Farnè, A., & Pavani, F. (2016). Bilateral representations of touch in the primary somatosensory cortex. Cognitive Neuropsychology, 33(1-2), 48-66. https://doi.org/10.1080/02643294.2016.1159547

Journal Article Type Article
Acceptance Date Feb 24, 2016
Online Publication Date Jun 17, 2016
Publication Date Feb 17, 2016
Deposit Date Jan 8, 2019
Journal Cognitive Neuropsychology
Print ISSN 0264-3294
Electronic ISSN 1464-0627
Publisher Routledge
Peer Reviewed Peer Reviewed
Volume 33
Issue 1-2
Pages 48-66
DOI https://doi.org/10.1080/02643294.2016.1159547
Public URL https://nottingham-repository.worktribe.com/output/1452026
Publisher URL https://www.tandfonline.com/doi/full/10.1080/02643294.2016.1159547
Additional Information Peer Review Statement: The publishing and review policy for this title is described in its Aims & Scope.; Aim & Scope: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=pcgn20