Delayed response tasks in basal ganglia lesions in man: further evidence for a striato-frontal cooperation in behavioural adaptation.
To determine the respective contribution of the subcortical structures and the prefrontal cortex in behavioural adaptation, we applied the delayed response paradigm, considered as a functional marker of the dorsolateral region of the prefrontal cortex, to patients with striatal dysfunction: Parkinson's disease (n = 27), progressive supranuclear palsy (n = 20); to patients with prefrontal lesions (n = 10) and to normal control subjects (n = 24). The performance of each group was compared in four experiments: a delayed response task in which the correct answer was previously indicated by an explicit cue (externally guided task); delayed alternation and non-alternation tasks coupled with a delayed reversal task in which the patient had to discover the rule by himself in the absence of explicit cues (internally driven tasks). All groups of patients showed a short-term spatial representational memory deficit in the externally guided situation. Patients with striatal dysfunction showed difficulties in re-engaging attention on a new programme and in maintaining it. However, they did not express the spontaneous tendency to alternate nor the severe difficulties in disengaging from a previous pattern of response demonstrated by patients with prefrontal lesions. These results validate the concept of a striato-frontal functional system in humans and suggest the existence of two different levels of behavioural organization: elaboration of new programmes of behaviour in association with inhibition of previously established ones, that might be under frontal lobe control: maintenance of the new programme until the action has been accomplished and automatization for a routine utilization, that might be under control of the striatum.
Partiot
A
A
INSERM U 289, Centre de Neuropsychologie, Hôpital de la Salpètrière, Paris, France.
Vérin
M
M
Pillon
B
B
Teixeira-Ferreira
C
C
Agid
Y
Y
Dubois
B
B
D000223:Adaptation, Psychological / Q000502:physiology*; D001480:Basal Ganglia Diseases / Q000503:physiopathology / Q000523:psychology*; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D017072:Neostriatum / Q000503:physiopathology*; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology / Q000523:psychology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013494:Supranuclear Palsy, Progressive / Q000503:physiopathology / Q000523:psychology; D014888:Wechsler Scales