Identifying peripersonal space boundaries in newborns

Abstract

Peripersonal space immediately surrounds the body and can be represented in the brain as a multisensory and sensorimotor interface mediating physical and social interactions between body and environment. Very little consideration has been given to the ontogeny of peripersonal spatial representations in early postnatal life, despite the crucial roles of peripersonal space and its adaptive relevance as the space where infants’ earliest interactions take place. Here, we investigated whether peripersonal space could be considered a delimited portion of space with defined boundaries soon after birth. Our findings showed for the first time that newborns’ saccadic reaction times to a tactile stimulus simultaneous to sounds with different intensities changed based on the sound intensity. In particular, they were significantly faster when the sound was lounder than a critical intensity, in a pattern that closely resembled that showed by adults. Therefore, provided that sound intensity on its own can cue newborns’ sound distance perception, we speculate that this critical distance could be considered the boundary of newborns’ rudimentary peripersonal space. Altogether, our findings suggest that soon after birth peripersonal space may be already considered as a bounded portion of space, perhaps instrumental to drive newborns’ attention towards events and people within it.

Visual-Tactile Spatial Multisensory Interaction in Adults With Autism and Schizophrenia

“…Finally, our study was cross-sectional. Peripersonal space representation can be measured shortly after birth (82) and may form the basis of an emerging sense of self in infancy and early toddlerhood (83), the period in which autism symptoms are first evident. Thus, prospective longitudinal studies of this phenomenon and related tests of bodily self-consciousness in infants at high genetic risk for autism or other neuropsychiatric conditions may shed important light on whether and how the development of the sense of self goes awry in these populations.…”

Sensorimotor representation learning for an "active self" in robots: A model survey

“…Instead of measuring the participants' vocal response time to tactile stimuli during an audio-tactile interaction task, they propose to measure the saccadic latency to visual targets (sRTs) as an indirect measure of infants' RTs. With the results of infants' sRTs showing a similar pattern as the adults' RTs, (Orioli et al, 2019) suggest that some sort of PPS boundaries exist already soon after birth, which facilitate the simultaneous multisensory matching in newborns.…”

“…While there is a body of studies on the representation of peripersonal space (PPS) in adults (see Section 3.3 for a brief review), there is very little research on this representation in infants, especially in their first months after birth. In a recent study, Orioli et al (2019) present a modified version of the reaction times (RTs) measurement, developed by (Canzoneri et al, 2012), to address the question whether the boundaries of the PPS representation is available in newborns. Instead of measuring the participants' vocal response time to tactile stimuli during an audio-tactile interaction task, they propose to measure the saccadic latency to visual targets (sRTs) as an indirect measure of infants' RTs.…”

The ontogeny of multisensory peripersonal space in human infancy: From visual-tactile links to conscious expectations

“…As such there may be a developmental offset between perceiving objects moving in peripersonal space and showing defensive reactions to such objects 18,19 . Other studies investigated the perception of multisensory events in peripersonal space, demonstrating that from an early age human infants are sensitive to temporal and spatial multisensory contingencies between visual, auditory and tactile stimuli that are likely to play a fundamental role in peripersonal space representations [20][21][22][23][24][25][26] . What remains unclear is the extent to which sensitivity to such multisensory contingencies can support infants' ability to create spatiotemporally coherent links between visual information specifying motion towards them and subsequent tactile stimulation on the body and, eventually, their ability to predict tactile bodily events.…”

“…Given the high adaptive value of perceiving and predicting the contact of visual objects with the body, it would be reasonable to expect that the mechanisms supporting it develop early in life 24 . At the same time, we believe that multisensory postnatal experience would most likely play an important role in infants' integration of stimuli approaching the body and subsequent tactile stimuli taking place at the expected time and location of contact.…”