title: Optic ataxia: from Balint's syndrome to the parietal reach region.
abstract: Optic ataxia is a high-order deficit in reaching to visual goals that occurs with posterior parietal cortex (PPC) lesions. It is a component of Balint's syndrome that also includes attentional and gaze disorders. Aspects of optic ataxia are misreaching in the contralesional visual field, difficulty preshaping the hand for grasping, and an inability to correct reaches online. Recent research in nonhuman primates (NHPs) suggests that many aspects of Balint's syndrome and optic ataxia are a result of damage to specific functional modules for reaching, saccades, grasp, attention, and state estimation. The deficits from large lesions in humans are probably composite effects from damage to combinations of these functional modules. Interactions between these modules, either within posterior parietal cortex or downstream within frontal cortex, may account for more complex behaviors such as hand-eye coordination and reach-to-grasp.
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA. Electronic address: andersen@vis.caltech.edu.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Andersen
authors.affiliation: Departments of Neurology and Pediatrics, University of California, Los Angeles Medical Center, Los Angeles, CA 90095, USA.
authors.forename: Kristen N
authors.initials: KN
authors.lastname: Andersen
authors.affiliation: Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Hwang
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Hauschild
mesh_terms: D000377:Agnosia / Q000503:physiopathology*; D000818:Animals; D001259:Ataxia / Q000503:physiopathology*; D001288:Attention / Q000502:physiology*; D006801:Humans; D010296:Parietal Lobe / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology*