title: Behavioral and neural correlates of communication via pointing.
abstract: Communicative pointing is a human specific gesture which allows sharing information about a visual item with another person. It sets up a three-way relationship between a subject who points, an addressee and an object. Yet psychophysical and neuroimaging studies have focused on non-communicative pointing, which implies a two-way relationship between a subject and an object without the involvement of an addressee, and makes such gesture comparable to touching or grasping. Thus, experimental data on the communicating function of pointing remain scarce. Here, we examine whether the communicative value of pointing modifies both its behavioral and neural correlates by comparing pointing with or without communication. We found that when healthy participants pointed repeatedly at the same object, the communicative interaction with an addressee induced a spatial reshaping of both the pointing trajectories and the endpoint variability. Our finding supports the hypothesis that a change in reference frame occurs when pointing conveys a communicative intention. In addition, measurement of regional cerebral blood flow using H(2)O(15) PET-scan showed that pointing when communicating with an addressee activated the right posterior superior temporal sulcus and the right medial prefrontal cortex, in contrast to pointing without communication. Such a right hemisphere network suggests that the communicative value of pointing is related to processes involved in taking another person's perspective. This study brings to light the need for future studies on communicative pointing and its neural correlates by unraveling the three-way relationship between subject, object and an addressee.
authors.affiliation: INSERM U955, Equipe 1, Neuropsychologie Interventionnelle, Institut Mondor de Recherche Biomédicale, Créteil, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Cleret de Langavant
authors.forename: Philippe
authors.initials: P
authors.lastname: Remy
authors.forename: Iris
authors.initials: I
authors.lastname: Trinkler
authors.forename: Joseph
authors.initials: J
authors.lastname: McIntyre
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Dupoux
authors.forename: Alain
authors.initials: A
authors.lastname: Berthoz
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Bachoud-Lévi
mesh_terms: D000328:Adult; D001519:Behavior / Q000502:physiology*; D001931:Brain Mapping; D003142:Communication; D005260:Female; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D049268:Positron-Emission Tomography