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Abstract:
Shallice (1982) proposed that all adaptive behavior of daily
living is supported by cognitive schemata (mental scripts) of these
activities, and that the selection and activation of these schemata
is implemented by two distinct cognitive mechanisms, a "controlled"
frontal system termed the Supervisory Attentional System (SAS) and
an "automatic" basal ganglia system termed the Contention
Programmer (CP). The goal of this investigation was to test this
model and to determine whether the now well known deleterious
effect of frontal lesions on recited mental scripts extends to a
behavioral scripting task, i.e., an ADL. Ten frontally lesioned
patients and 10 age and education and gender matched controls
received a battery of neuropsychological tests, a script recitation
task, and an ADL task consisting of preparing a three course meal.
The patients had more problems on the ADL task than on the
neuropsychological tests or script recitation task. More
specifically, the patients had major difficulty with the
macrostructure of the task (initiating the strategically correct
actions and coordinating timing of the meal's end point components)
and less with the microstructure (the overlearned mini-sequences,
such as grilling a steak). We conclude that ADL scripts are very
sensitive to frontal lesions, and that frontal lesions impair the
SAS and not the CP in this particular context, as predicted by
Shallice.
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