Ipsilateral stimulus encoding in primary and secondary somatosensory cortex of awake mice

Tactile Stimuli ◽

Somatosensory Cortices ◽

Stimulus Responsive ◽

Layer 4

Lateralization is a hallmark of somatosensory processing in the mammalian brain. However, in addition to their contralateral representation, unilateral tactile stimuli also modulate neuronal activity in somatosensory cortices of the ipsilateral hemisphere. The cellular organization and functional role of these ipsilateral stimulus responses in awake somatosensory cortices, especially regarding stimulus coding, are unknown. Here, we targeted silicon probe recordings to the vibrissa region of primary (S1) and secondary (S2) somatosensory cortex of awake head-fixed male and female mice while delivering ipsilateral and contralateral whisker stimuli. Ipsilateral stimuli drove larger and more reliable responses in S2 than in S1, and activated a larger fraction of stimulus-responsive neurons. Ipsilateral stimulus-responsive neurons were rare in layer 4 of S1, but were located in equal proportion across all layers in S2. Linear classifier analyses further revealed that decoding of the ipsilateral stimulus was more accurate in S2 than S1, while S1 decoded contralateral stimuli most accurately. These results reveal substantial encoding of ipsilateral stimuli in S1 and especially S2, consistent with the hypothesis that higher cortical areas may integrate tactile inputs across larger portions of space, spanning both sides of the body.

Effects of looming and static sounds on somatosensory processing: A MEG study

Seeing and Perceiving ◽

10.1163/187847612x647270 ◽

2012 ◽

Vol 25 (0) ◽

pp. 94

Author(s):

Elisa Leonardelli ◽

Valeria Occelli ◽

Gianpaolo Demarchi ◽

Massimo Grassi ◽

Christoph Braun ◽

...

Keyword(s):

Somatosensory Cortex ◽

Time Window ◽

The Body ◽

Head Model ◽

Global Field Power ◽

Head Space ◽

Extrapersonal Space ◽

Significant Difference

The present study aims to assess the mechanisms involved in the processing of potentially threatening stimuli presented within the peri-head space of humans. Magnetic fields evoked by air-puffs presented at the peri-oral area of fifteen participants were recorded by using magnetoencephalography (MEG). Crucially, each air puff was preceded by a sound, which could be either perceived as looming, stationary and close to the body (i.e., within the peri-head space) or stationary and far from the body (i.e., extrapersonal space). The comparison of the time courses of the global field power (GFP) indicated a significant difference in the time window ranging from 70 to 170 ms between the conditions. When the air puff was preceded by a stationary sound located far from the head stronger somatosensory activity was evoked as compared to the conditions where the sounds were located close to the head. No difference could be shown for the looming and the stationary prime stimulus close to the head. Source localization was performed assuming a pair of symmetric dipoles in a spherical head model that was fitted to the MRI images of the individual participants. Results showed sources in primary and secondary somatosensory cortex. Source activities in secondary somatosensory cortex differed between the three conditions, with larger effects evoked by the looming sounds and smaller effects evoked by the far stationary sounds, and the close stationary sounds evoking intermediate effects. Overall, these findings suggest the existence of a system involved in the detection of approaching objects and protecting the body from collisions in humans.

Seasonal plasticity in the adult somatosensory cortex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1922888117 ◽

2020 ◽

Vol 117 (50) ◽

pp. 32136-32144

Author(s):

Saikat Ray ◽

Miao Li ◽

Stefan Paul Koch ◽

Susanne Mueller ◽

Philipp Boehm-Sturm ◽

...

Keyword(s):

Somatosensory Cortex ◽

Activity Patterns ◽

Adaptive Plasticity ◽

Neural Systems ◽

Mammalian Brain ◽

Sensory Stimuli ◽

Seasonal Plasticity ◽

Layer 4 ◽

Life On Earth

Seasonal cycles govern life on earth, from setting the time for the mating season to influencing migrations and governing physiological conditions like hibernation. The effect of such changing conditions on behavior is well-appreciated, but their impact on the brain remains virtually unknown. We investigate long-term seasonal changes in the mammalian brain, known as Dehnel’s effect, where animals exhibit plasticity in body and brain sizes to counter metabolic demands in winter. We find large seasonal variation in cellular architecture and neuronal activity in the smallest terrestrial mammal, the Etruscan shrew, Suncus etruscus. Their brain, and specifically their neocortex, shrinks in winter. Shrews are tactile hunters, and information from whiskers first reaches the somatosensory cortex layer 4, which exhibits a reduced width (−28%) in winter. Layer 4 width (+29%) and neuron number (+42%) increase the following summer. Activity patterns in the somatosensory cortex show a prominent reduction of touch-suppressed neurons in layer 4 (−55%), the most metabolically active layer. Loss of inhibitory gating occurs with a reduction in parvalbumin-positive interneurons, one of the most active neuronal subtypes and the main regulators of inhibition in layer 4. Thus, a reduction in neurons in layer 4 and particularly parvalbumin-positive interneurons may incur direct metabolic benefits. However, changes in cortical balance can also affect the threshold for detecting sensory stimuli and impact prey choice, as observed in wild shrews. Thus, seasonal neural adaptation can offer synergistic metabolic and behavioral benefits to the organism and offer insights on how neural systems show adaptive plasticity in response to ecological demands.

Somatosensory Processing in the Human Inferior Prefrontal Cortex

Journal of Neurophysiology ◽

10.1152/jn.2002.88.3.1400 ◽

2002 ◽

Vol 88 (3) ◽

pp. 1400-1406 ◽

Cited By ~ 38

Author(s):

Matthew C. Hagen ◽

David H. Zald ◽

Tricia A. Thornton ◽

José V. Pardo

Keyword(s):

Inferior Frontal Gyrus ◽

Sensory Stimulation ◽

Brain Regions ◽

Somatosensory Stimulation ◽

Tactile Stimuli ◽

Somatosensory Cortices ◽

Frontal Operculum ◽

Frontal Activity ◽

Ventral Area

Three inferior prefrontal regions in the monkey receive afferents from somatosensory cortices: the orbitofrontal cortex (OFC), the ventral area of the principal sulcus, and the anterior frontal operculum. To determine whether these areas show responses to tactile stimuli in humans, we examined data from an ongoing series of PET studies of somatosensory processing. Unlike previous work showing ventral frontal activity to hedonic (pleasant/unpleasant) sensory stimulation, the tactile stimuli used in these studies had a neutral hedonic valence. Our data provide evidence for at least two discrete ventral frontal brain regions responsive to somatosensory stimulation: 1) the posterior inferior frontal gyrus (IFG) and adjacent anterior frontal operculum, and 2) the OFC. The former region (posterior IFG/anterior frontal operculum) may have a more specific role in attending to tactile stimuli.

Differential Organization of Touch and Pain in Human Primary Somatosensory Cortex

Journal of Neurophysiology ◽

10.1152/jn.2000.83.3.1770 ◽

2000 ◽

Vol 83 (3) ◽

pp. 1770-1776 ◽

Cited By ~ 128

Author(s):

Markus Ploner ◽

Frank Schmitz ◽

Hans-Joachim Freund ◽

Alfons Schnitzler

Keyword(s):

Somatosensory Cortex ◽

Pain Perception ◽

Hierarchical Organization ◽

Primary Somatosensory Cortex ◽

Nociceptive Response ◽

Tactile Stimuli ◽

Somatosensory Cortices ◽

Cortical Responses ◽

Nociceptive Processing ◽

Nociceptive Afferents

Processing of tactile stimuli within somatosensory cortices has been shown to be complex and hierarchically organized. However, the precise organization of nociceptive processing within these cortices has remained largely unknown. We used whole-head magnetoencephalography to directly compare cortical responses to stimulation of tactile and nociceptive afferents of the dorsum of the hand in humans. Within the primary somatosensory cortex (SI), nociceptive stimuli activated a single source whereas tactile stimuli activated two sequentially peaking sources. Along the postcentral gyrus, the nociceptive SI source was located 10 mm more medially than the early tactile SI response arising from cytoarchitectonical area 3b and corresponded spatially to the later tactile SI response. Considering a mediolateral location difference between the hand representations of cytoarchitectonical areas 3b and 1, the present results suggest generation of the single nociceptive response in area 1, whereas tactile stimuli activate sequentially peaking sources in areas 3b and 1. Thus nociceptive processing apparently does not share the complex and hierarchical organization of tactile processing subserving elaborated sensory capacities. This difference in the organization of both modalities may reflect that pain perception rather requires reactions to and avoidance of harmful stimuli than sophisticated sensory capacities.

Attenuation of sensory processing in the primary somatosensory cortex during rubber hand illusion

Scientific Reports ◽

10.1038/s41598-021-86828-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Masanori Sakamoto ◽

Hirotoshi Ifuku

Keyword(s):

Somatosensory Cortex ◽

Sensory Processing ◽

The Body ◽

Neural Representation ◽

Rubber Hand Illusion ◽

Primary Somatosensory Cortex ◽

Rubber Hand ◽

Factors Influencing ◽

The Brain

AbstractThe neural representation of the body is easily altered by the integration of multiple sensory signals in the brain. The “rubber hand illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, a feeling of ownership of the rubber hand is created. Some studies have shown that somatosensory processing in the brain is attenuated when RHI occurs. However, it is unknown where attenuation of somatosensory processing occurs. Here, we show that somatosensory processing is attenuated in the primary somatosensory cortex. We found that the earliest response of somatosensory evoked potentials, which is thought to originate from the primary somatosensory cortex, was attenuated during RHI. Furthermore, this attenuation was observed before the occurrence of the illusion. Our results suggest that attenuation of sensory processing in the primary somatosensory cortex is one of the factors influencing the occurrence of the RHI.

A cortico-cortical pathway targets inhibitory interneurons and modulates paw movement during locomotion in mice

10.1101/2021.09.23.461507 ◽

2021 ◽

Author(s):

Chia-wei Chang ◽

Meiling Zhao ◽

Samantha Grudzien ◽

Max F Oginsky ◽

Yexin Yang ◽

...

Keyword(s):

Somatosensory Cortex ◽

Primary Motor Cortex ◽

Brain Slices ◽

Movement Control ◽

Inhibitory Interneuron ◽

The Body ◽

Male And Female ◽

Female Mice ◽

Cortical Inputs

The primary somatosensory cortex (S1) is important for the control of movement as it encodes sensory input from the body periphery and external environment during ongoing movement. Mouse S1 consists of several distinct sensorimotor subnetworks that receive topographically organized cortico-cortical inputs from distant sensorimotor areas, including the secondary somatosensory cortex (S2) and primary motor cortex (M1). The role of the vibrissal S1 area and associated cortical connections during active sensing is well documented, but whether (and if so, how) non-whisker S1 areas are involved in movement control remains relatively unexplored. Here, we demonstrate that unilateral silencing of the non-whisker S1 area in both male and female mice disrupts hind paw movement during locomotion on a rotarod and a runway. S2 and M1 provide major long range inputs to this S1 area. Silencing S2 to non whisker S1 projections alters the hind paw orientation during locomotion while manipulation of the M1 projection has little effect. Using patch clamp recordings in brain slices from male and female mice, we show that S2 projection preferentially innervates inhibitory interneuron subtypes. We conclude that S2 S1 corticocortical interactions mediated by local interneurons are critical for efficient locomotion.

It feels like it’s me: Interpersonal multisensory stimulation enhances visual remapping of touch from other to self

Seeing and Perceiving ◽

10.1163/187847612x648422 ◽

2012 ◽

Vol 25 (0) ◽

pp. 215-216 ◽

Cited By ~ 1

Author(s):

Flavia Cardini ◽

Ana Tajadura-Jiménez ◽

Andrea Serino ◽

Manos Tsakiris

Keyword(s):

Social Interactions ◽

The Body ◽

The Self ◽

Perceived Similarity ◽

Multisensory Stimulation ◽

Self And Other ◽

Sensory Experiences ◽

Tactile Stimuli ◽

The Face

We constantly feel, see and move our body, and have no doubt that it is our own, distinct from the body of other people. At the same time, understanding other people’s feelings in social interactions depends on the ability to map onto one’s own body the observed experiences on the bodies of others. It has been shown that the more similar others are perceived to be to our self, the stronger this mapping is. While previous studies have focused on existing similarities or differences between self and other, we ask whether the experimental change of the self-other boundaries can lead to changes in somatosensory processing. It has been shown that the perception of tactile stimuli on the face is enhanced if participants concurrently observe a face being touched. This Visual Remapping of Touch (VRT; Ladavas and Serino, 2010) is enhanced the more similar others are perceived to be to the self, and is strongest when viewing one’s face (Serino et al., 2008, 2009). We used the enfacement illusion that relies on synchronous interpersonal multisensory stimulation (IMS; Sforza et al., 2010; Tsakiris, 2008) to manipulate self-other boundaries. Following synchronous, but not asynchronous IMS, the self-related enhancement of the VRT effect was extended to the other individual. These findings suggest that shared multi-sensory experiences represent one key way in which the boundaries and perceived similarity between self and others can be overcome, as evidenced by changes in somatosensory processing of shared tactile stimuli.

An ERP Investigation on Visuotactile Interactions in Peripersonal and Extrapersonal Space: Evidence for the Spatial Rule

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2009.21109 ◽

2009 ◽

Vol 21 (8) ◽

pp. 1550-1559 ◽

Cited By ~ 43

Author(s):

Chiara F. Sambo ◽

Bettina Forster

Keyword(s):

Somatosensory Cortex ◽

Multisensory Integration ◽

Visual Stimuli ◽

Spatial Relationship ◽

Time Range ◽

Spatial Effects ◽

Extrapersonal Space ◽

Tactile Stimuli ◽

Visuotactile Interactions

The spatial rule of multisensory integration holds that cross-modal stimuli presented from the same spatial location result in enhanced multisensory integration. The present study investigated whether processing within the somatosensory cortex reflects the strength of cross-modal visuotactile interactions depending on the spatial relationship between visual and tactile stimuli. Visual stimuli were task-irrelevant and were presented simultaneously with touch in peripersonal and extrapersonal space, in the same or opposite hemispace with respect to the tactile stimuli. Participants directed their attention to one of their hands to detect infrequent tactile target stimuli at that hand while ignoring tactile targets at the unattended hand, all tactile nontarget stimuli, and any visual stimuli. Enhancement of ERPs recorded over and close to the somatosensory cortex was present as early as 100 msec after onset of stimuli (i.e., overlapping with the P100 component) when visual stimuli were presented next to the site of tactile stimulation (i.e., perihand space) compared to when these were presented at different locations in peripersonal or extrapersonal space. Therefore, this study provides electrophysiological support for the spatial rule of visual–tactile interaction in human participants. Importantly, these early cross-modal spatial effects occurred regardless of the locus of attention. In addition, and in line with previous research, we found attentional modulations of somatosensory processing only to be present in the time range of the N140 component and for longer latencies with an enhanced negativity for tactile stimuli at attended compared to unattended locations. Taken together, the pattern of the results from this study suggests that visuotactile spatial effects on somatosensory processing occur prior and independent of tactile–spatial attention.

The Sense of Touch: Embodied Simulation in a Visuotactile Mirroring Mechanism for Observed Animate or Inanimate Touch

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2008.20111 ◽

2008 ◽

Vol 20 (9) ◽

pp. 1611-1623 ◽

Cited By ~ 129

Author(s):

Sjoerd J. H. Ebisch ◽

Mauro G. Perrucci ◽

Antonio Ferretti ◽

Cosimo Del Gratta ◽

Gian Luca Romani ◽

...

Keyword(s):

Somatosensory Cortex ◽

Precentral Gyrus ◽

Video Clips ◽

Somatosensory Cortices ◽

Significant Difference ◽

Human Tendency ◽

Abstract Notion ◽

Sense Of Touch ◽

Healthy Participants

Previous studies have shown a shared neural circuitry in the somatosensory cortices for the experience of one's own body being touched and the sight of intentional touch. Using functional magnetic resonance imaging (fMRI), the present study aimed to elucidate whether the activation of a visuotactile mirroring mechanism during touch observation applies to the sight of any touch, that is, whether it is independent of the intentionality of observed touching agent. During fMRI scanning, healthy participants viewed video clips depicting a touch that was intentional or accidental, and occurring between animate or inanimate objects. Analyses showed equal overlapping activation for all the touch observation conditions and the experience of one's own body being touched in the bilateral secondary somatosensory cortex (SII), left inferior parietal lobule (IPL)/supramarginal gyrus, bilateral temporal-occipital junction, and left precentral gyrus. A significant difference between the sight of an intentional touch, compared to an accidental touch, was found in the left primary somatosensory cortex (SI/Brodmann's area [BA] 2). Interestingly, activation in SI/BA 2 significantly correlated with the degree of intentionality of the observed touch stimuli as rated by participants. Our findings show that activation of a visuotactile mirroring mechanism for touch observation might underpin an abstract notion of touch, whereas activation in SI might reflect a human tendency to “resonate” more with a present or assumed intentional touching agent.

Attenuated Input to the Primary Somatosensory Cortex is Associated with the Occurrence of Rubber Hand Illusion

10.21203/rs.3.rs-141539/v1 ◽

2021 ◽

Author(s):

Masanori Sakamoto ◽

Hirotoshi Ifuku

Keyword(s):

Somatosensory Cortex ◽

Early Response ◽

The Body ◽

Neural Representation ◽

Rubber Hand Illusion ◽

Primary Somatosensory Cortex ◽

Rubber Hand ◽

Somatosensory Input ◽

The Brain

Abstract The neural representation of the body is easily altered by the integration of multiple sensory signals in the brain. The “rubber hand illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, ownership of the rubber hand is created. Some studies have shown that somatosensory processing in the brain is attenuated when RHI occurs. However, it is unknown where attenuation of somatosensory inputs occurs. Here, we show that somatosensory input from the hand is attenuated at the primary somatosensory cortex. We found that the early response of somatosensory evoked potential, which is thought to originate from the primary somatosensory cortex, was attenuated during RHI. Furthermore, this attenuation was observed before the occurrence of the illusion. Our results suggest that attenuation of somatosensory inputs from the hand to the brain is one of the factors influencing the occurrence of the RHI.