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The space surrounding the body, and the regulation of this buffer zone play a central role in adaptive behavior, with direct implications for psychopathology. The physical distance that we choose to maintain between ourselves and others for social comfort is known as Interpersonal Distance (IPD), whereas the action space that marks the perceptual border between the self and the external world is known as Peripersonal Space (PPS ). While both IPD and PPS represent personal space, they are distinct constructs, each associated with different methodologies. Here we review the existing literature on IPD and PPS to elucidate their distinct and common contributions to psychiatric conditions including schizophrenia, autism, anxiety, and others. Altered representation and regulation of IPD and PPS were associated with clinical symptoms and social impairments across a wide range of psychiatric disorders, underscoring the important role of the self-other boundary and personal space regulation in adaptive social behavior. Future research should clarify the relationship between IPD and PPS and specify risk factors for self-other boundary dysregulation and associated psychopathologies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Prior studies have found that individuals with schizophrenia often have an enlarged "personal space". However, the neurocognitive mechanisms underlying this consistent finding remain unknown., Methods: The well-validated Stop Distance Procedure was used to measure the personal space preferences of individuals with psychotic disorders (PD, N = 22) and demographically-matched healthy controls (HC, N = 20) in response to human and virtual (avatar) intruders. Physiological arousal and subjective discomfort were measured during intrusions into personal space and modeled across different interpersonal distances. Additionally, participants were interviewed to assess their subjective awareness of their personal space preferences., Results: Personal space measurements with humans and avatars were highly correlated and reliable over repeated trials, and influenced by the displayed emotion and gender of the intruders, in both groups. The PD group exhibited a larger personal space than the HC group (all p < 0.028), and the size of personal space with avatar intruders was significantly correlated with positive symptom severity in the PD subjects. Moreover, the magnitude of arousal responses to personal space intrusions was proportional to a power (exponent) of the distance between subjects and intruders, with a significantly smaller exponent in the PD (compared to the HC) for both human (p = 0.026) and avatar (p = 0.011) intruders, indicating a less steep function. Lastly, much of the participants' qualitative impressions of their personal space behaviors were consistent or correlated with the quantitative findings, reflecting some awareness of the determinants of personal space., Conclusions: These findings reveal both intact and altered aspects of personal space regulation in psychotic disorders, and the potential utility of personal space measurements, given their high reliability, to serve as objective targets of interventions., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Personal space has been defined as "the area individuals maintain around themselves into which others cannot intrude without arousing discomfort". However, the precise relationship between discomfort (or arousal) responses as a function of distance from an observer remains incompletely understood. Also the mechanisms involved in recognizing conspecifics and distinguishing them from other objects within personal space have not been identified. Accordingly, here we measured personal space preferences in response to real humans and human-like avatars (in virtual reality), using well-validated "stop distance" procedures. Based on threshold measurements of personal space, we examined within-subject variations in discomfort-related responses across multiple distances (spanning inside and outside each individual's personal space boundary), as reflected by psychological (ratings) and physiological (skin conductance) responses to both humans and avatars. We found that the discomfort-by-distance functions for both humans and avatars were closely fit by a power law. These results suggest that the brain computation of visually-defined personal space begins with a 'rough sketch' stage, which generates responses to a broad range of human-like stimuli, in addition to humans. Analogous processing mechanisms may underlie other brain functions which respond similarly to both real and simulated human body parts., (© 2021. The Author(s).)

Background: Attachment, or affiliative bonding among conspecifics, is thought to involve neural mechanisms underlying behavioral responses to threat and reward-related social signals. However, attachment-oriented responses may also rely on basic sensorimotor processes. One sensorimotor system that may play a role in attachment is the parietofrontal cortical network that responds to stimuli that are near or approaching the body, the peripersonal space (PPS) monitoring system. We hypothesized that this network may vary in responsivity to such potentially harmful stimuli, particularly those with social salience, based on individual differences in attachment styles., Methods: Young adults viewed images of human faces or cars that appeared to move towards or away from them, while functional magnetic resonance imaging data were collected. Correlations between each of four adult attachment styles, measured using the Relationship Questionnaire, and responses of the PPS network to approaching (versus withdrawing) stimuli were measured., Results: A region-of-interest (ROI) analysis, focused on six cortical regions of the PPS network that showed significant responses to approaching versus withdrawing face stimuli in an independent sample (n = 80), revealed that anxious attachment style (but not the other 3 attachment styles) was significantly positively correlated with responses to faces (but not to cars) in all six ROIs (r = 0.33-0.49, p = 0.01-0.0001, n = 50)., Conclusions: These findings suggest that anxious attachment is associated with over-responsivity of a sensorimotor network involved in attending to social stimuli near the body., (Copyright © 2021. Published by Elsevier Inc.)

Schizophrenia is associated with subtle abnormalities in day-to-day social behaviors, including a tendency in some patients to "keep their distance" from others in physical space. The neural basis of this abnormality, and related changes in social functioning, is unknown. Here we examined, in schizophrenic patients and healthy control subjects, the functioning of a parietal-frontal network involved in monitoring the space immediately surrounding the body ("personal space"). Using fMRI, we found that one region of this network, the dorsal intraparietal sulcus (DIPS), was hyper-responsive in schizophrenic patients to face stimuli appearing to move towards the subjects, intruding into personal space. This hyper-responsivity was predicted both by the size of personal space (which was abnormally elevated in the schizophrenia group) and the severity of negative symptoms. In contrast, in a second study, the activity of two lower-level visual areas that send information to DIPS (the fusiform face area and middle temporal area) was normal in schizophrenia. Together, these findings suggest that changes in parietal-frontal networks that support the sensory-guided initiation of behavior, including actions occurring in the space surrounding the body, contribute to social dysfunction and negative symptoms in schizophrenia.

A parietal-frontal network in primates is thought to support many behaviors occurring in the space around the body, including interpersonal interactions and maintenance of a particular "comfort zone" or distance from other people ("personal space"). To better understand this network in humans, we used functional MRI to measure the responses to moving objects (faces, cars, simple spheres) and the functional connectivity of two regions in this network, the dorsal intraparietal sulcus (DIPS) and the ventral premotor cortex (PMv). We found that both areas responded more strongly to faces that were moving toward (vs away from) subjects, but did not show this bias in response to comparable motion in control stimuli (cars or spheres). Moreover, these two regions were functionally interconnected. Tests of activity-behavior associations revealed that the strength of DIPS-PMv connectivity was correlated with the preferred distance that subjects chose to stand from an unfamiliar person (personal space size). In addition, the magnitude of DIPS and PMv responses was correlated with the preferred level of social activity. Together, these findings suggest that this parietal-frontal network plays a role in everyday interactions with others.

Personal space (PS) is the space around the body that people prefer to maintain between themselves and unfamiliar others. Intrusion into personal space evokes discomfort and an urge to move away. Physiologic studies in nonhuman primates suggest that defensive responses to intruding stimuli involve the parietal cortex. We hypothesized that the spatial encoding of interpersonal distance is initially transformed from purely sensory to more egocentric mapping within human parietal cortex. This hypothesis was tested using 7 Tesla (7T) fMRI at high spatial resolution (1.1 mm isotropic), in seven subjects (four females, three males). In response to visual stimuli presented at a range of virtual distances, we found two categories of distance encoding in two corresponding radially-extending columns of activity within parietal cortex. One set of columns (P columns) responded selectively to moving and stationary face images presented at virtual distances that were nearer (but not farther) than each subject's behaviorally-defined personal space boundary. In most P columns, BOLD response amplitudes increased monotonically and nonlinearly with increasing virtual face proximity. In the remaining P columns, BOLD responses decreased with increasing proximity. A second set of parietal columns (D columns) responded selectively to disparity-based distance cues (near or far) in random dot stimuli, similar to disparity-selective columns described previously in occipital cortex. Critically, in parietal cortex, P columns were topographically interdigitated (nonoverlapping) with D columns. These results suggest that visual spatial information is transformed from visual to body-centered (or person-centered) dimensions in multiple local sites within human parietal cortex. [ABSTRACT FROM AUTHOR]

Personal space is the distance that people tend to maintain from others during daily life in a largely unconscious manner. For humans, personal space-related behaviors represent one form of non-verbal social communication, similar to facial expressions and eye contact. Given that the changes in social behavior and experiences that occurred during the COVID-19 pandemic, including “social distancing” and widespread social isolation, may have altered personal space preferences, we investigated this possibility in two independent samples. First, we compared the size of personal space measured before the onset of the pandemic to its size during the pandemic in separate groups of subjects. Personal space size was significantly larger in those assessed during (compared to those assessed before) the onset of the pandemic (all d > 0.613, all p < 0.007). In an additional cohort, we measured personal space size, and discomfort in response to intrusions into personal space, longitudinally before and during the pandemic, using both conventional and virtual reality-based techniques. Within these subjects, we found that measurements of personal space size with respect to real versus virtual humans were significantly correlated with one another (r = 0.625–0.958) and similar in magnitude. Moreover, the size of personal space, as well as levels of discomfort during personal space intrusions, increased significantly during (compared to before) the COVID-19 pandemic in response to both real and virtual humans (all d > 0.842, all p < 0.01). Lastly, we found that the practice of social distancing and perceived (but not actual) risk of being infected with COVID-19 were linked to this personal space enlargement during the pandemic (all p < 0.038). Taken together, these findings suggest that personal space boundaries expanded during the COVID-19 pandemic independent of actual infection risk level. As the day-to-day effects of the pandemic subside, personal space preferences may provide one index of recovery from the psychological effects of this crisis. [ABSTRACT FROM AUTHOR]

Background Changes in the regulation of interpersonal distance, or "personal space" (PS), have been repeatedly observed in schizophrenia and, in some studies, linked to negative symptoms. However, the neurobiological basis of these impairments is poorly understood. Methods Personal space measurements, functional connectivity of a brain network sensitive to intrusions into PS, and symptoms of social withdrawal and anhedonia were assessed, and associations among these outcomes measured, in 33 individuals with a psychotic disorder (primarily schizophrenia [SCZ]) and 36 control subjects (CON). Results Personal space size was significantly higher (P =.002) and PS permeability (reflecting the capacity to tolerate intrusions into PS) was significantly lower (P =.021) in the SCZ relative to the CON group, and both measures were significantly correlated with social anhedonia and withdrawal in the full sample (all P <.007). Moreover, functional connectivity between the PS and default mode (DM) networks was significantly correlated with the permeability, but not the size, of PS in the full sample and in the SCZ and CON groups separately, and with social withdrawal in the SCZ group. Lastly, the association between PS-DM network connectivity and social withdrawal in the SCZ group was fully mediated by PS permeability. Discussion Neural and behavioral aspects of PS regulation are linked to social motivation in both healthy individuals and those with psychotic disorders, suggesting that measurements of PS could serve as transdiagnostic markers of social functioning. [ABSTRACT FROM AUTHOR]