title: Human posterior parietal cortex encodes the movement goal in a pro-/anti-reach task.
abstract: Previous research on reach planning in humans has implicated a frontoparietal network, including the precuneus (PCu), a putative human homolog of the monkey parietal reach region (PRR), and the dorsal premotor cortex (PMd). Using a pro-/anti-reach task, electrophysiological studies in monkeys have demonstrated that the movement goal rather than the location of the visual cue is encoded in PRR and PMd. However, if only the effector but not the movement goal is specified (underspecified condition), the PRR and PMd have been shown to represent all potential movement goals. In this functional magnetic resonance imaging study, we investigated whether the human PCu and PMd likewise encode the movement goal, and whether these reach-related areas also engage in situations with underspecified compared with specified movement goals. By using a pro-/anti-reach task, we spatially dissociated the location of the visual cue from the location of the movement goal. In the specified conditions, pro- and anti-reaches activated similar parietal and premotor areas. In the PCu contralateral to the moving arm, we found directionally selective activation fixed to the movement goal. In the underspecified conditions, we observed activation in reach-related areas of the posterior parietal cortex, including PCu. However, the activation was substantially weaker in parietal areas and lacking in PMd. Our results suggest that human PCu encodes the movement goal rather than the location of the visual cue if the movement goal is specified and even engages in situations when only the visual cue but not the movement goal is defined.
authors.affiliation: Department of Psychology, Justus-Liebig University Giessen, Giessen, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Gertz
authors.affiliation: Department of Psychology, Justus-Liebig University Giessen, Giessen, Germany Katja.Fiehler@psychol.uni-giessen.de.
authors.forename: Katja
authors.initials: K
authors.lastname: Fiehler
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006040:Goals; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult
keywords: human functional magnetic resonance imaging; precuneus; premotor cortex; reach planning; visuomotor integration