Tactile information from the human hand reaches the ipsilateral primary somatosensory cortex

Nociception, somatic discriminative aspects of pain, is represented in the primary somatosensory cortex (S1), as is touch, but the separation and the interaction of the two modalities within S1 remain unclear. Here, we show the spatially-distinct tactile and nociceptive processing in the granular barrel field (BF) and the adjacent dysgranular region (Dys) in mouse S1. Simultaneous recording of the multiunit activity across subregions reveals that Dys responses are selective to noxious input whereas those of BF are to tactile input. At the single neuron level, nociceptive information is represented separately from the tactile information in Dys layer 2/3. In contrast, both modalities are converged in a layer 5 neuron in each region. Interestingly, the two modalities interfere with each other in both regions. We further demonstrate that Dys, but not BF, activity is critically involved in neuropathic pain and pain behavior, and thus provide evidence that Dys is a center specialized for nociception in S1.

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Reach Out and Touch Someone: Anticipatory Sensorimotor Processes of Active Interpersonal Touch

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00610 ◽

2014 ◽

Vol 26 (9) ◽

pp. 2171-2185 ◽

Cited By ~ 12

Author(s):

Sjoerd J. H. Ebisch ◽

Francesca Ferri ◽

Gian Luca Romani ◽

Vittorio Gallese

Keyword(s):

Social Behavior ◽

Somatosensory Cortex ◽

Temporal Cortex ◽

Somatosensory System ◽

Primary Somatosensory Cortex ◽

Human Hand ◽

Skin Contact ◽

Interpersonal Touch ◽

Medial Pfc ◽

Sensorimotor Processes

Anticipating the sensorimotor consequences of an action for both self and other is fundamental for action coordination when individuals socially interact. Somatosensation constitutes an elementary component of social cognition and sensorimotor prediction, but its functions in active social behavior remain unclear. We hypothesized that the somatosensory system contributes to social haptic behavior as evidenced by specific anticipatory activation patterns when touching an animate target (human hand) compared with an inanimate target (fake hand). fMRI scanning was performed during a paradigm that allowed us to isolate the anticipatory representations of active interpersonal touch while controlling for nonsocial sensorimotor processes and possible confounds because of interpersonal relationships or socioemotional valence. Active interpersonal touch was studied both as skin-to-skin contact and as object-mediated touch. The results showed weaker deactivation in primary somatosensory cortex and medial pFC and stronger activation in cerebellum for the animate target, compared with the inanimate target, when intending to touch it with one's own hand. Differently, in anticipation of touching the human hand with an object, anterior inferior parietal lobule and lateral occipital-temporal cortex showed stronger activity. When actually touching a human hand with one's own hand, activation was stronger in medial pFC but weaker in primary somatosensory cortex. The findings provide new insight on the contribution of simulation and sensory prediction mechanisms to active social behavior. They also suggest that literally getting in touch with someone and touching someone by using an object might be approached by an agent as functionally distinct conditions.

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Cortical and thalamic contributions to response dynamics across layers of the primary somatosensory cortex during tactile discrimination

Journal of Neurophysiology ◽

10.1152/jn.00108.2015 ◽

2015 ◽

Vol 114 (3) ◽

pp. 1652-1676 ◽

Cited By ~ 9

Author(s):

Miguel Pais-Vieira ◽

Carolina Kunicki ◽

Po-He Tseng ◽

Joel Martin ◽

Mikhail Lebedev ◽

...

Keyword(s):

Information Processing ◽

Somatosensory Cortex ◽

Information Transfer ◽

Primary Somatosensory Cortex ◽

Neural Dynamics ◽

Response Dynamics ◽

Tactile Discrimination ◽

Tactile Information ◽

Medial Nucleus ◽

Posterior Medial Nucleus

Tactile information processing in the rodent primary somatosensory cortex (S1) is layer specific and involves modulations from both thalamocortical and cortico-cortical loops. However, the extent to which these loops influence the dynamics of the primary somatosensory cortex while animals execute tactile discrimination remains largely unknown. Here, we describe neural dynamics of S1 layers across the multiple epochs defining a tactile discrimination task. We observed that neuronal ensembles within different layers of the S1 cortex exhibited significantly distinct neurophysiological properties, which constantly changed across the behavioral states that defined a tactile discrimination. Neural dynamics present in supragranular and granular layers generally matched the patterns observed in the ventral posterior medial nucleus of the thalamus (VPM), whereas the neural dynamics recorded from infragranular layers generally matched the patterns from the posterior nucleus of the thalamus (POM). Selective inactivation of contralateral S1 specifically switched infragranular neural dynamics from POM-like to those resembling VPM neurons. Meanwhile, ipsilateral M1 inactivation profoundly modulated the firing suppression observed in infragranular layers. This latter effect was counterbalanced by contralateral S1 block. Tactile stimulus encoding was layer specific and selectively affected by M1 or contralateral S1 inactivation. Lastly, causal information transfer occurred between all neurons in all S1 layers but was maximal from infragranular to the granular layer. These results suggest that tactile information processing in the S1 of awake behaving rodents is layer specific and state dependent and that its dynamics depend on the asynchronous convergence of modulations originating from ipsilateral M1 and contralateral S1.

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Unconscious Touch Perception After Disruption of the Primary Somatosensory Cortex

Psychological Science ◽

10.1177/0956797620970551 ◽

2021 ◽

pp. 095679762097055

Author(s):

Tony Ro ◽

Lua Koenig

Keyword(s):

Somatosensory Cortex ◽

Visual Information ◽

Control Site ◽

Primary Somatosensory Cortex ◽

Tactile Information ◽

Touch Perception ◽

Contralateral Hand ◽

Sensory Cortices ◽

Transient Loss ◽

The Brain

Brain damage or disruption to the primary visual cortex sometimes produces blindsight, a striking condition in which patients lose the ability to consciously detect visual information yet retain the ability to discriminate some attributes without awareness. Although there have been few demonstrations of somatosensory equivalents of blindsight, the lesions that produce “numbsense,” in which patients can make accurate guesses about tactile information without awareness, have been rare and localized to different regions of the brain. Despite transient loss of tactile awareness in the contralateral hand after transcranial magnetic stimulation (TMS) of the primary somatosensory cortex but not TMS of a control site, 12 participants (six female) reliably performed at above-chance levels on a localization task. These results demonstrating TMS-induced numbsense implicate a parallel somatosensory pathway that processes the location of touch in the absence of awareness and highlight the importance of primary sensory cortices for conscious perception.

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