Deficit in conditional visuomotor learning by local infusion of bicuculline into the ventral prefrontal cortex in monkeys.
To explore the role of the ventral prefrontal cortex (PFv) in conditional visuomotor learning, we infused locally bicuculline, a GABAergic antagonist, into the PFv of two monkeys, well trained on a two-problem visuomotor task. The task required the monkeys to execute one of two motor actions (moving a handle to the left or to the right) in response to one of two familiar visual patterns (circle or triangle). The two patterns mapped 1:1 onto the two motor actions: for each pattern one and only one motor action was scored, correct and reinforced. In contrast to these sessions with familiar patterns, in the learning sessions the monkeys were presented with one or two novel patterns and required to learn the arbitrarily determined associations between these patterns and the two motor actions. We found that bilateral infusion of bicuculline into PFv dramatically impaired the monkeys' ability to learn novel pattern-response associations: the trials and errors to criterion (90% correct) increased significantly. The errors were mainly an inability to apply 'Win-Stay', 'Lose-Shift' and 'Change-Shift' strategies. There was no effect on the monkeys' performance in responding to familiar patterns. Similar infusion of bicuculline into the dorsal prefrontal cortex was without effect on either novel-pattern learning or familiar-pattern performance. We conclude that the ventral prefrontal cortex is necessary for learning new visuomotor associations, but has less importance, if any, for performing pre-established ones.
Wang
M
M
Shanghai Institute of Physiology and Shanghai Research Center of Life Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, The People's Republic of China.
Zhang
H
H
Li
B M
BM
D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology; D001640:Bicuculline / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009483:Neuropsychological Tests; D010363:Pattern Recognition, Automated; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D014795:Visual Pathways / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D005680:gamma-Aminobutyric Acid; D001640:Bicuculline