Deficits in saccade target selection after inactivation of superior colliculus.
Saccades are rapid eye movements that orient gaze toward areas of interest in the visual scene. Neural activity correlated with saccade target selection has been identified in several brain regions, including the superior colliculus (SC), but it is not known whether the SC is directly involved in target selection, or whether the SC merely receives selection-related signals from cortex in preparation for the execution of eye movements. In monkeys, we used focal reversible inactivation to test the functional contributions of the SC to target selection during visual search, and found that inactivation resulted in clear deficits. When a target appeared in the inactivated field, saccades were often misdirected to distractor stimuli. Control tasks showed that this deficit was not caused by low-level visual or motor impairments. Our results indicate that, in addition to its well-established involvement in movement execution, the SC has an important functional role in target selection.
McPeek
Robert M
RM
The Smith-Kettlewell Eye Research Institute, 2318 Fillmore Street, San Francisco, California 94115, USA. rmm@ski.org
Keller
Edward L
EL
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal; D004192:Discrimination, Psychological / Q000187:drug effects; D005403:Fixation, Ocular / Q000502:physiology; D007839:Functional Laterality; D018755:GABA Agonists / Q000494:pharmacology; D008012:Lidocaine / Q000494:pharmacology; D008253:Macaca mulatta; D008845:Microinjections / Q000379:methods; D009118:Muscimol / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000187:drug effects / Q000528:radiation effects; D011930:Reaction Time / Q000187:drug effects / Q000528:radiation effects; D012438:Saccades / Q000187:drug effects / Q000502:physiology*; D013477:Superior Colliculi / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D014796:Visual Perception / Q000187:drug effects / Q000502:physiology*
D000779:Anesthetics, Local; D018755:GABA Agonists; D009118:Muscimol; D008012:Lidocaine