title: Mixed Body/Hand Reference Frame for Reaching in 3D Space in Macaque Parietal Area PEc.
abstract: The neural correlates of coordinate transformations from vision to action are expressed in the activity of posterior parietal cortex (PPC). It has been demonstrated that among the medial-most areas of the PPC, reaching targets are represented mainly in hand-centered coordinates in area PE, and in eye-centered, body-centered, and mixed body/hand-centered coordinates in area V6A. Here, we assessed whether neurons of area PEc, located between V6A and PE in the medial PPC, encode targets in body-centered, hand-centered, or mixed frame of reference during planning and execution of reaching. We studied 104 PEc cells in 3 Macaca fascicularis. The animals performed a reaching task toward foveated targets located at different depths and directions in darkness, starting with the hand from 2 positions located at different depths, one next to the trunk and the other far from it. We show that most PEc neurons encoded targets in a mixed body/hand-centered frame of reference. Although the effect of hand position was often rather strong, it was not as strong as reported previously in area PE. Our results suggest that area PEc represents an intermediate node in the gradual transformation from vision to action that takes place in the reaching network of the dorsomedial PPC.
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Piserchia
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Breveglieri
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.|Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Kostas
authors.initials: K
authors.lastname: Hadjidimitrakis
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Bertozzi
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Galletti
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Fattori
mesh_terms: D000200:Action Potentials; D000818:Animals; D006225:Hand / Q000502:physiology*; D008252:Macaca fascicularis; D008297:Male; D008839:Microelectrodes; D009043:Motor Activity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D013028:Space Perception / Q000502:physiology*; D060726:Torso / Q000502:physiology
keywords: depth; hand; reach coordinates; spatial coordinates; visuomotor transformations