Common and distinct brain regions processing multisensory bodily signals for peripersonal space and body ownership

A network of brain regions including the ventral premotor cortex (vPMc) and the posterior parietal cortex (PPc) is consistently recruited during processing of multisensory stimuli within peripersonal space (PPS). However, to date, information on the causal role of these fronto-parietal areas in multisensory PPS representation is lacking. Using low-frequency repetitive TMS (rTMS; 1 Hz), we induced transient virtual lesions to the left vPMc, PPc, and visual cortex (V1, control site) and tested whether rTMS affected audio–tactile interaction in the PPS around the hand. Subjects performed a timed response task to a tactile stimulus on their right (contralateral to rTMS) hand while concurrent task-irrelevant sounds were presented either close to the hand or 1 m far from the hand. When no rTMS was delivered, a sound close to the hand reduced RT-to-tactile targets as compared with when a far sound was presented. This space-dependent, auditory modulation of tactile perception was specific to a hand-centered reference frame. Such a specific form of multisensory interaction near the hand can be taken as a behavioral hallmark of PPS representation. Crucially, virtual lesions to vPMc and PPc, but not to V1, eliminated the speeding effect due to near sounds, showing a disruption of audio–tactile interactions around the hand. These findings indicate that multisensory interaction around the hand depends on the functions of vPMc and PPc, thus pointing to the necessity of this human fronto-parietal network in multisensory representation of PPS.

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Reaching Out to See: Arm Position Can Attenuate Human Visual Loss

Journal of Cognitive Neuroscience ◽

10.1162/0898929041502698 ◽

2004 ◽

Vol 16 (6) ◽

pp. 935-943 ◽

Cited By ~ 64

Author(s):

Krista Schendel ◽

Lynn C. Robertson

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Visual Stimuli ◽

Peripersonal Space ◽

Brain Regions ◽

Visual Responses ◽

Visual Ability ◽

Arm Position ◽

Visual Hemifield ◽

Novel Approach

Electrophysiological recordings in monkeys have now revealed several brain regions that contain bimodal visuotactile neurons capable of responding to either tactile or visual stimuli placed on or near the hands, arms, and face. These cells have now been found in frontal, parietal, and subcortical areas of the monkey brain, suggesting a cortical network of neurons that preferentially represent near peripersonal space. The degree to which the visual responses of such cells rely on input from the primary visual cortex and the extent to which they may contribute to visual perception is not completely understood. Nonetheless, recent neuropsychological studies suggest that a similar representation of near space may be bimodally coded in humans as well. Given the accumulating evidence for specialized processing of visual stimuli placed near the hands and arms, we hypothesized that arm position may be capable of modulating human visual ability. Here we report the case of WM, who lost his ability to see in his left visual hemifield after sustaining damage to his right primary visual cortex. Interestingly, the placement of WM's left arm into his “blind” field resulted in significantly better detection of left visual field stimuli compared to when his hand was placed in his lap at midline. Moreover, we found this attenuation to be confined to stimuli presented within reaching distance (unless a tool that extended WM's reach was held while he performed the test). These findings are highly consistent with the characteristics of the bimodal visuo-tactile neurons that have been described in monkeys. Thus, it seems that arm position can modulate human visual ability, even after damage to the primary visual cortex. This study provides an exciting bridge between monkey neurophysiology and human visual capacity while also offering a novel approach for improving visual defects acquired via cortical injury.

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Spatio-temporal Perception and Boundaries of Self: Evaluation of Peripersonal Space in Schizotypy Traits

European Psychiatry ◽

10.1016/j.eurpsy.2017.01.2041 ◽

2017 ◽

Vol 41 (S1) ◽

pp. S162-S163

Author(s):

G. Di Cosmo ◽

F. Fiori ◽

F. Ferri ◽

A. Salone ◽

M. Corbo ◽

...

Keyword(s):

Personal Space ◽

Peripersonal Space ◽

Brain Regions ◽

Schizotypal Personality ◽

Self Evaluation ◽

Interactive Behavior ◽

Accurate Judgment ◽

The Social ◽

Spatio Temporal ◽

Competing Interest

IntroductionThe peripersonal space is described as that area within the boundary between self and non-self. An accurate judgment of peripersonal space boundaries may depend on the capacity to create an organized and structured mental representation that integrates signals from different sensory modalities and brain regions. Empirical evidence suggests that these functions are altered in schizotypy, which is thought to reflect the subclinical expression of the symptoms of schizophrenia in the general population. A number of clinical studies reported that interpersonal interaction and social stimulation have an impact on the onset and progress of schizophrenia.ObjectivesWe conducted a study on personal space in a sample of student screened for schizotypal traits using a paradigm that was not affected by emotional and social interference.AimsThe aim was to evaluate the relationship between personal space and schizotypy traits.MethodsThirty-four subject recruited for the study completed the Schizotypal Personality Questionnaire (SPQ). According to the SPQ results participants were splitted into two groups (High, Low). Each participant performed a PeriPersonal Space (PPS) task.ResultsOur results show a more extended boundary of the peripersonal space in people with high schizotypy compared to people with low schizotypy even without emotional and social interference.ConclusionsPeople with high traits of schizotypy suffer from a difficulty in social integration because of being unable to adapt the social behavior. A better understanding of the mechanisms for abnormal interactive behavior could provide significant valid guidelines for innovating insertion programs that aims to improve social functioning.Disclosure of interestThe authors have not supplied their declaration of competing interest.

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