title: Effects of Microstimulation in the Anterior Intraparietal Area during Three-Dimensional Shape Categorization.
abstract: The anterior intraparietal area (AIP) of rhesus monkeys is part of the dorsal visual stream and contains neurons whose visual response properties are commensurate with a role in three-dimensional (3D) shape perception. Neuronal responses in AIP signal the depth structure of disparity-defined 3D shapes, reflect the choices of monkeys while they categorize 3D shapes, and mirror the behavioral variability across different stimulus conditions during 3D-shape categorization. However, direct evidence for a role of AIP in 3D-shape perception has been lacking. We trained rhesus monkeys to categorize disparity-defined 3D shapes and examined AIP's contribution to 3D-shape categorization by microstimulating in clusters of 3D-shape selective AIP neurons during task performance. We find that microstimulation effects on choices (monkey M1) and reaction times (monkey M1 and M2) depend on the 3D-shape preference of the stimulated site. Moreover, electrical stimulation of the same cells, during either the 3D-shape-categorization task or a saccade task, could affect behavior differently. Interestingly, in one monkey we observed a strong correlation between the strength of choice-related AIP activity (choice probabilities) and the influence of microstimulation on 3D-shape-categorization behavior (choices and reaction time). These findings propose AIP as part of the network responsible for 3D-shape perception. The results also show that the anterior intraparietal cortex contains cells with different tuning properties, i.e. 3D-shape- or saccade-related, that can be dynamically read out depending on the requirements of the task at hand.
authors: Laboratorium voor Neuro- en Psychofysiologie, O&N2, Campus Gasthuisberg, KU Leuven, Leuven, Belgium; Department of Neurobiology, The University of Chicago, Chicago, Illinois, United States of America.
authors: Bram-Ernst
authors: BE
authors: Verhoef
authors: Laboratorium voor Neuro- en Psychofysiologie, O&N2, Campus Gasthuisberg, KU Leuven, Leuven, Belgium.
authors: Rufin
authors: R
authors: Vogels
authors: Laboratorium voor Neuro- en Psychofysiologie, O&N2, Campus Gasthuisberg, KU Leuven, Leuven, Belgium.
authors: Peter
authors: P
authors: Janssen
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000502:physiology; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D005260:Female; D005556:Form Perception / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D008839:Microelectrodes; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time; D012438:Saccades / Q000502:physiology; D013238:Stereotaxic Techniques; D013647:Task Performance and Analysis; D015357:Vision Disparity / Q000502:physiology