Functional role of the basal ganglia in the planning and execution of actions.
OBJECTIVE
Recent studies of functional brain imaging have shown the involvement of the basal ganglia in executive processes such as planning and set-shifting. However, the specific contributions of the striatum in those processes remain unknown. This study aimed to test the hypothesis that the caudate nucleus is primarily involved in the preparation of a novel action and not in set-shifting per se.


METHODS
In the present event-related functional magnetic resonance imaging (fMRI) study, a new task was developed that permitted, for the first time, to distinguish between shifts in classification when the rule is implicitly given by the task from shifts that require cognitive comparison and planning.


RESULTS
Significantly increased activity in the caudate nucleus and the putamen was observed only in conditions in which cognitive planning was required to perform a set-shift, whereas significant activation was seen in the subthalamic nucleus (another region of the basal ganglia) in all shifting conditions whether or not planning was required.


CONCLUSIONS
We suggest that the caudate nucleus and the putamen are particularly important, respectively, in the planning and the execution of a self-generated novel action, whereas the subthalamic nucleus may be required when a new motor program is solicited independently of the choice of strategy.
Monchi
Oury
O
Functional Neuroimaging Unit, Centre de Recherhe, Institut Universitaire de Gériatrie de Montréal, Québec, Canada. oury.monchi@umontreal.ca
Petrides
Michael
M
Strafella
Antonio P
AP
Worsley
Keith J
KJ
Doyon
Julien
J
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001479:Basal Ganglia / Q000033:anatomy & histology / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D002421:Caudate Nucleus / Q000098:blood supply / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D011939:Mental Recall / Q000502:physiology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation / Q000379:methods; D011340:Problem Solving / Q000502:physiology*
D010100:Oxygen