title: Putative pyramidal neurons and interneurons in the monkey parietal cortex make different contributions to the performance of a visual grouping task.
abstract: Visual grouping of discrete elements is an important function for object recognition. We recently conducted an experiment to study neural correlates of visual grouping. We recorded neuronal activities while monkeys performed a grouping detection task in which they discriminated visual patterns composed of discrete dots arranged in a cross and detected targets in which dots with the same contrast were aligned horizontally or vertically. We found that some neurons in the lateral bank of the intraparietal sulcus exhibit activity related to visual grouping. In the present study, we analyzed how different types of neurons contribute to visual grouping. We classified the recorded neurons as putative pyramidal neurons or putative interneurons, depending on the duration of their action potentials. We found that putative pyramidal neurons exhibited selectivity for the orientation of the target, and this selectivity was enhanced by attention to a particular target orientation. By contrast, putative interneurons responded more strongly to the target stimuli than to the nontargets, regardless of the orientation of the target. These results suggest that different classes of parietal neurons contribute differently to the grouping of discrete elements.
authors.affiliation: Div. of Sensory and Cognitive Information, National Institute for Physiological Sciences, Myoudaiji, Okazaki, 444-8585 Aichi, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Yokoi
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Komatsu
mesh_terms: D000818:Animals; D000882:Haplorhini; D007395:Interneurons / Q000502:physiology*; D008251:Macaca; D008297:Male; D009474:Neurons / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*