title: Multiple representation of reaching space in the medial posterior parietal area V6A.
abstract: During foveal reaching, the activity of neurons in the macaque medial posterior parietal area V6A is modulated by both gaze and arm direction. In the present work, we dissociated the position of gaze and reaching targets, and studied the neural activity of single V6A cells while the eyes and reaching targets were arranged in different spatial configurations (peripheral and foveal combinations). Target position influenced neural activity in all stages of the task, from visual presentation of target and movement planning, through reach execution and holding time. The majority of neurons preferred reaches directed toward peripheral targets, rather than foveal. Most neurons discharged in both premovement and action epochs. In most cases, reaching activity was tuned coherently across action planning and execution. When reaches were planned and executed in different eye/target configurations, multiple analyses revealed that few neurons coded reaching actions according to the absolute position of target, or to the position of target relative to the eye. The majority of cells responded to a combination of both these factors. These data suggest that V6A contains multiple representations of spatial information for reaching, consistent with a role of this area in forming cross-reference frame representations to be used by premotor cortex.
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Bosco
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Breveglieri
authors.affiliation: Department of Physiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Reser
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Galletti
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Fattori
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001288:Attention; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D008252:Macaca fascicularis; D008297:Male; D009068:Movement / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D010296:Parietal Lobe / Q000166:cytology* / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors
keywords: coordinate transformations; dorsal visual stream; frames of reference; pointing movement