title: Intertrial Variability in the Premotor Cortex Accounts for Individual Differences in Peripersonal Space.
abstract: We live in a dynamic environment, constantly confronted with approaching objects that we may either avoid or be forced to address. A multisensory and sensorimotor interface, the peripersonal space (PPS), mediates every physical interaction between our body and the environment. Behavioral investigations show high variability in the extension of PPS across individuals, but there is a lack of evidence on the neural underpinnings of these large individual differences. Here, we used approaching auditory stimuli and fMRI to capture the individual boundary of PPS and examine its neural underpinnings. Precisely, we tested the hypothesis that intertrial variability (ITV) in brain regions coding PPS predicts individual differences of its boundary at the behavioral level. Selectively in the premotor cortex, we found that ITV, rather than trial-averaged amplitude, of BOLD responses to far rather than near dynamic stimuli predicts the individual extension of PPS. Our results provide the first empirical support for the relevance of ITV of brain responses for individual differences in human behavior.
  
  
  CONCLUSIONS
  Peripersonal space (PPS) is a multisensory and sensorimotor interface mediating every physical interaction between the body and the environment. A major characteristic of the boundary of PPS in humans is the extremely high variability of its location across individuals. We show that interindividual differences in the extension of the PPS are predicted by variability of BOLD responses in the premotor cortex to far stimuli approaching our body. Our results provide the first empirical support to the relevance of variability of evoked responses for human behavior and its variance across individuals.
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario K1Z 7K4, Canada, and fraferri78@gmail.com.
authors.forename: Francesca
authors.identifier: http://orcid.org/0000-0003-1821-5870
authors.initials: F
authors.lastname: Ferri
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario K1Z 7K4, Canada, and Department of Neuroscience, Imaging, and Clinical Science, G. d'Annunzio University of Chieti and Institute for Advanced Biomedical Technologies, Chieti 66100, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Costantini
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario K1Z 7K4, Canada, and.
authors.forename: Zirui
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Neuroscience, Imaging, and Clinical Science, G. d'Annunzio University of Chieti and Institute for Advanced Biomedical Technologies, Chieti 66100, Italy.
authors.forename: Mauro Gianni
authors.initials: MG
authors.lastname: Perrucci
authors.affiliation: Department of Neuroscience, Imaging, and Clinical Science, G. d'Annunzio University of Chieti and Institute for Advanced Biomedical Technologies, Chieti 66100, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ferretti
authors.affiliation: Department of Neuroscience, Imaging, and Clinical Science, G. d'Annunzio University of Chieti and Institute for Advanced Biomedical Technologies, Chieti 66100, Italy.
authors.forename: Gian Luca
authors.initials: GL
authors.lastname: Romani
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario K1Z 7K4, Canada, and.
authors.forename: Georg
authors.initials: G
authors.lastname: Northoff
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001519:Behavior / Q000502:physiology; D004777:Environment; D005260:Female; D006801:Humans; D007206:Individuality; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010550:Personal Space; D010812:Physical Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013017:Sound Localization / Q000502:physiology; D014110:Touch / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: fMRI; interindividual differences; intertrial variability of brain response; looming sounds; peripersonal space