Visuo-tactile predictive mechanisms of peripersonal space

Author(s):  
H.C. Dijkerman ◽  
W.P. Medendorp

Our daily living includes bodily contacts with objects and people. While this physical contact occurs naturally, it could also pose a risk of bodily harm—for example, when objects are sharp, or people have bad intentions. It is therefore imperative to have a mechanism that predicts the consequences of bodily contact before it occurs, to guide our interactions appropriately. Evidence from a range of studies suggests a neurofunctional coupling between external visual or auditory stimuli near the body and tactile stimuli on the body. While these multisensory peripersonal representations have been linked to spatial attention, motor control, and social behaviour, a discussion on whether these functions involve a similar mechanism has been missing. Here we suggest that prediction is central to this multimodal coding: visual or auditory stimuli near the body predict tactile consequences of bodily contact. This predictive mechanism is based on learned visuo-tactile associations and modulated by higher-order visual contextual information.

2020 ◽  
Vol 14 ◽  
Author(s):  
Daniela Rabellino ◽  
Paul A. Frewen ◽  
Margaret C. McKinnon ◽  
Ruth A. Lanius

Peripersonal space (PPS) is defined as the space surrounding the body where we can reach or be reached by external entities, including objects or other individuals. PPS is an essential component of bodily self-consciousness that allows us to perform actions in the world (e.g., grasping and manipulating objects) and protect our body while interacting with the surrounding environment. Multisensory processing plays a critical role in PPS representation, facilitating not only to situate ourselves in space but also assisting in the localization of external entities at a close distance from our bodies. Such abilities appear especially crucial when an external entity (a sound, an object, or a person) is approaching us, thereby allowing the assessment of the salience of a potential incoming threat. Accordingly, PPS represents a key aspect of social cognitive processes operational when we interact with other people (for example, in a dynamic dyad). The underpinnings of PPS have been investigated largely in human models and in animals and include the operation of dedicated multimodal neurons (neurons that respond specifically to co-occurring stimuli from different perceptive modalities, e.g., auditory and tactile stimuli) within brain regions involved in sensorimotor processing (ventral intraparietal sulcus, ventral premotor cortex), interoception (insula), and visual recognition (lateral occipital cortex). Although the defensive role of the PPS has been observed in psychopathology (e.g., in phobias) the relation between PPS and altered states of bodily consciousness remains largely unexplored. Specifically, PPS representation in trauma-related disorders, where altered states of consciousness can involve dissociation from the body and its surroundings, have not been investigated. Accordingly, we review here: (1) the behavioral and neurobiological literature surrounding trauma-related disorders and its relevance to PPS; and (2) outline future research directions aimed at examining altered states of bodily self-consciousness in trauma related-disorders.


2019 ◽  
Vol 30 (10) ◽  
pp. 1522-1532 ◽  
Author(s):  
Tomohiro Amemiya ◽  
Yasushi Ikei ◽  
Michiteru Kitazaki

The limited space immediately surrounding our body, known as peripersonal space (PPS), has been investigated by focusing on changes in the multisensory processing of audio-tactile stimuli occurring within or outside the PPS. Some studies have reported that the PPS representation is extended by body actions such as walking. However, it is unclear whether the PPS changes when a walking-like sensation is induced but the body neither moves nor is forced to move. Here, we show that a rhythmic pattern consisting of walking-sound vibrations applied to the soles of the feet, but not the forearms, boosted tactile processing when looming sounds were located near the body. The findings suggest that an extension of the PPS representation can be triggered by stimulating the soles in the absence of body action, which may automatically drive a motor program for walking, leading to a change in spatial cognition around the body.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marine Taffou ◽  
Clara Suied ◽  
Isabelle Viaud-Delmon

AbstractAuditory roughness elicits aversion, and higher activation in cerebral areas involved in threat processing, but its link with defensive behavior is unknown. Defensive behaviors are triggered by intrusions into the space immediately surrounding the body, called peripersonal space (PPS). Integrating multisensory information in PPS is crucial to assure the protection of the body. Here, we assessed the behavioral effects of roughness on auditory-tactile integration, which reflects the monitoring of this multisensory region of space. Healthy human participants had to detect as fast as possible a tactile stimulation delivered on their hand while an irrelevant sound was approaching them from the rear hemifield. The sound was either a simple harmonic sound or a rough sound, processed through binaural rendering so that the virtual sound source was looming towards participants. The rough sound speeded tactile reaction times at a farther distance from the body than the non-rough sound. This indicates that PPS, as estimated here via auditory-tactile integration, is sensitive to auditory roughness. Auditory roughness modifies the behavioral relevance of simple auditory events in relation to the body. Even without emotional or social contextual information, auditory roughness constitutes an innate threat cue that elicits defensive responses.


2021 ◽  
pp. 1-18
Author(s):  
Chiara Spaccasassi ◽  
Chris H. Dijkerman ◽  
Angelo Maravita ◽  
Oscar Ferrante ◽  
Maartje C. de Jong

Abstract The space around our body, the so-called “peripersonal space,” is where interactions with nearby objects may occur. “Defensive space” and “Reaching space” respectively refer to two opposite poles of interaction between our body and the external environment: protecting the body and performing a goal-directed action. Here, we hypothesized that mechanisms underlying these two action spaces are differentially modulated by the valence of visual stimuli, as stimuli with negative valence are more likely to activate protective actions whereas stimuli with positive valence may activate approaching actions. To test whether such distinction in cognitive/evaluative processing exists between Reaching and Defensive spaces, we measured behavioral responses as well as neural activations over sensorimotor cortex using EEG while participants performed several tasks designed to tap into mechanisms underlying either Defensive (e.g., respond to touch) or Reaching space (e.g., estimate whether object is within reaching distance). During each task, pictures of objects with either positive or negative valence were presented at different distances from the participants' body. We found that Defensive space was smaller for positively compared with negatively valenced visual stimuli. Furthermore, sensorimotor cortex activation (reflected in modulation of beta power) during tactile processing was enhanced when coupled with negatively rather than positively valenced visual stimuli regarding Defensive space. On the contrary, both the EEG and behavioral measures capturing the mechanisms underlying Reaching space did not reveal any modulation by valence. Thus, although valence encoding had differential effects on Reaching and Defensive spaces, the distance of the visual stimulus modulated behavioral measures as well as activity over sensorimotor cortex (reflected in modulations of mu power) in a similar way for both types of spaces. Our results are compatible with the idea that Reaching and Defensive spaces involve the same distance-dependent neural representations of sensory input, whereas task goals and stimulus valence (i.e., contextual information) are implemented at a later processing stage and exert an influence on motor output rather than sensory/space encoding.


2016 ◽  
Author(s):  
Roy Salomon ◽  
Jean-Paul Noel ◽  
Marta Łukowska ◽  
Nathan Faivre ◽  
Thomas Metzinger ◽  
...  

AbstractRecent studies have highlighted the role of multisensory integration as a key mechanism of self-consciousness. In particular, integration of bodily signals within the peripersonal space (PPS) underlies the experience of the self in a body we own (self-identification) and that is experienced as occupying a specific location in space (self-location), two main components of bodily self-consciousness (BSC). Experiments investigating the effects of multisensory integration on BSC have typically employed supra-threshold sensory stimuli, neglecting the role of unconscious sensory signals in BSC, as tested in other consciousness research. Here, we used psychophysical techniques to test whether multisensory integration of bodily stimuli underlying BSC may also occur for multisensory inputs presented below the threshold of conscious perception. Our results indicate that visual stimuli rendered invisible (through continuous flash suppression) boost processing of tactile stimuli on the body (Exp. 1), and enhance the perception of near-threshold tactile stimuli (Exp. 2), only once they entered peripersonal space. We then employed unconscious multisensory mechanisms to manipulate BSC. Participants were presented with tactile stimulation on their body and with visual stimuli on a virtual body, seen at a distance, which were either visible or rendered invisible. We report that if visuo-tactile stimulation was synchronized, participants self-identified with the virtual body (Exp. 3), and shifted their self-location toward the virtual body (Exp.4), even if visual stimuli were fully invisible. Our results indicate that multisensory inputs, even outside of awareness, are integrated and affect the phenomenological content of self-consciousness, grounding BSC firmly in the field of psychophysical consciousness studies.


2002 ◽  
Vol 13 (4) ◽  
pp. 350-355 ◽  
Author(s):  
Angelo Maravita ◽  
Charles Spence ◽  
Claire Sergent ◽  
Jon Driver

In mirror reflections, visual stimuli in near peripersonal space (e.g., an object in the hand) can project the retinal image of far, extrapersonal stimuli “beyond” the mirror. We studied the interaction of such visual reflections with tactile stimuli in a cross-modal congruency task. We found that visual distractors produce stronger interference on tactile judgments when placed close to the stimulated hand, but observed indirectly as distant mirror reflections, than when directly observed in equivalently distant far space, even when in contact with a dummy hand or someone else's hand in the far location. The stronger visual-tactile interference for the mirror condition implies that near stimuli seen as distant reflections in a mirror view of one's own hands can activate neural networks coding peripersonal space, because these visual stimuli are coded as having a true source near to the body.


2020 ◽  
Author(s):  
Giulia Orioli ◽  
Irene Parisi ◽  
José L. van Velzen ◽  
Andrew J. Bremner

AbstractThe influence of visual object motion on the processing of bodily events offers a marker for the development of human infants’ perception of themselves in peripersonal space. We presented 4- (n = 20) and 8-month-old (n = 20) infants with an unattended visual object moving towards or away from their body followed by a vibrotactile stimulus on their hands. The 4-month-olds’ somatosensory evoked potentials (SEPs) were modulated by approaching visual motion, demonstrating the early ontogeny of the cortical multisensory foundations of peripersonal space representations. We also observed rapid changes in these markers within the 8-month-old age group: as infants approach 9 months, salient SEP components were increasingly enhanced by (unexpected) tactile stimuli following receding visual motion. These findings provide important clues to the ontogeny of human self-awareness in the first year of life, and suggest important postnatal developments in infants’ expectations about interactions between the body and the external world.


2002 ◽  
Vol 14 (7) ◽  
pp. 1030-1043 ◽  
Author(s):  
Alessandro Farnè ◽  
Elisabetta Làdavas

In the present study we report neuropsychological evidence of the existence of an auditory peripersonal space representation around the head in humans and its characteristics. In a group of right brain-damaged patients with tactile extinction, we found that a sound delivered near the ipsilesional side of the head (20 cm) strongly extinguished a tactile stimulus delivered to the contralesional side of the head (cross-modal auditory-tactile extinction). By contrast, when an auditory stimulus was presented far from the head (70 cm), cross-modal extinction was dramatically reduced. This spatially specific cross-modal extinction was most consistently found (i.e., both in the front and back spaces) when a complex sound was presented, like a white noise burst. Pure tones produced spatially specific cross-modal extinction when presented in the back space, but not in the front space. In addition, the most severe cross-modal extinction emerged when sounds came from behind the head, thus showing that the back space is more sensitive than the front space to the sensory interaction of auditory-tactile inputs. Finally, when cross-modal effects were investigated by reversing the spatial arrangement of cross-modal stimuli (i.e., touch on the right and sound on the left), we found that an ipsilesional tactile stimulus, although inducing a small amount of cross-modal tactile-auditory extinction, did not produce any spatial-specific effect. Therefore, the selective aspects of cross-modal interaction found near the head cannot be explained by a competition between a damaged left spatial representation and an intact right spatial representation. Thus, consistent with neurophysiological evidence from monkeys, our findings strongly support the existence, in humans, of an integrated cross-modal system coding auditory and tactile stimuli near the body, that is, in the peripersonal space.


Author(s):  
Samuel B. Hunley ◽  
Arwen M. Marker ◽  
Stella F. Lourenco

Abstract. The current study investigated individual differences in the flexibility of peripersonal space (i.e., representational space near the body), specifically in relation to trait claustrophobic fear (i.e., fear of suffocating or being physically restricted). Participants completed a line bisection task with either a laser pointer (Laser condition), allowing for a baseline measure of the size of one’s peripersonal space, or a stick (Stick condition), which produces expansion of one’s peripersonal space. Our results revealed that individuals high in claustrophobic fear had larger peripersonal spaces than those lower in claustrophobic fear, replicating previous research. We also found that, whereas individuals low in claustrophobic fear demonstrated the expected expansion of peripersonal space in the Stick condition, individuals high in claustrophobic fear showed less expansion, suggesting decreased flexibility. We discuss these findings in relation to the defensive function of peripersonal space and reduced attentional flexibility associated with trait anxieties.


2016 ◽  
Vol 136 (8) ◽  
pp. 1135-1141
Author(s):  
Ryo Hasegawa ◽  
Amir Maleki ◽  
Masafumi Uchida
Keyword(s):  
The Body ◽  

Sign in / Sign up

Export Citation Format

Share Document