title: Saccadic target selection deficits after lateral intraparietal area inactivation in monkeys.
abstract: We investigated the contribution of the lateral intraparietal area (LIP) to the selection of saccadic eye movement targets and to saccade execution using muscimol-induced reversible inactivation and compared those effects with inactivation of the adjacent ventral intraparietal area (VIP) and with sham injections of saline into LIP. Three types of tasks were used: saccades to single visual or memorized targets, saccades to synchronous and asynchronous bilateral targets, and visual search of a target among distractors. LIP inactivation failed to produce deficits in the latency or accuracy of saccades to single targets, but it dramatically reduced the frequency of contralateral saccades in the presence of bilateral targets, and it increased search time for a contralateral target during serial visual search. In the latter task, the observed deficits might reflect either an ispilateral bias in saccadic search strategy or an attentional impairment in locating a target among flanking distractors within the contralateral field. No effects were observed on any of these tasks after VIP inactivation. These results suggest that one important contribution of LIP to oculomotor behavior is the selection of targets for saccades in the context of competing visual stimuli.
authors.affiliation: Institut des Sciences Cognitives, Unité Mixte de Recherche 5015 Centre National de la Recherche Scientifique-Université Claude Bernard Lyon 1, 69675 Bron Cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Wardak
authors.forename: Etienne
authors.initials: E
authors.lastname: Olivier
authors.forename: Jean-René
authors.initials: JR
authors.lastname: Duhamel
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D005403:Fixation, Ocular / Q000187:drug effects / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D008253:Macaca mulatta; D008568:Memory / Q000502:physiology; D009118:Muscimol / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010296:Parietal Lobe / Q000187:drug effects / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000187:drug effects; D012438:Saccades / Q000187:drug effects / Q000502:physiology*
chemical_list: D018755:GABA Agonists; D009118:Muscimol