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Abstract:
The cerebellum is recognized as an important component in
neural systems involved in sensorimotor learning. It has been
suggested that, as part of a more general role in cognition, the
cerebellum may contribute to non-motor learning. To examine this
hypothesis, we tested a group of patients with cerebellar lesions
and matched controls on a series of perceptual categorization
tasks. Sinusoidal gratings, varying in spatial frequency (i.e.,
grating width) and orientation, were divided into two categories. A
trial-and-error learning procedure was adopted with 500-700 trials
per categorization task. In the single-dimension conditions,
optimal performance required that the stimuli be divided on the
basis of either the frequency or orientation dimension, only. In
the mixed-dimension condition, optimal performance required
attending to both dimensions. Previous studies have associated the
single- and mixed-dimension conditions with explicit and implicit
learning strategies, respectively. Consistent with this
distinction, learning in the single-dimension conditions was
relatively abrupt, with asymptotic performance achieved within the
first 100 trials. In contrast, learning within the mixed-dimension
condition was gradual. The patients performed comparable to the
control group in both the single- and mixed-dimension conditions.
These initial results suggest that acquired cerebellar lesions do
not disrupt non-motor learning. Follow-up studies will examine more
difficult categorization tasks using a model-based analysis to
examine strategy choice and application.
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