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Abstract:
The perception of time and the production of timed behaviors
depend on the interplay of hypothetical central timekeepers with
other processes, including attention and working memory. The neural
systems that support different component processes of timed
behaviors are controversial. To investigate the role of the
cerebellum, 21 patients with cerebellar lesions and 30 control
subjects performed time discriminations and reproduced time
intervals. Independent measures of attention
(engaging/disengaging), working memory (Digit Span), and
cognitive-motor speed (maximum tapping speed) were also obtained.
Time perception and reproduction accuracy were normal in patients,
suggesting the cerebellum does not directly regulate timekeeping
operations. There was a nonsignificant trend for time perception
acuity (difference thresholds) deficits, only in patients with
superior cerebellar hemisphere lesions. Time reproduction
variability, attributed to "clock" but not "motor implementation"
sources (Wing & Kristofferson, 1973), was significantly
elevated only in patients with superior cerebellar hemisphere
lesions. Working memory and attentional capacity did not explain
performance in either timing task. Cognitive-motor speed correlated
with perceptual acuity for time (r=.68) and with clock (r=.43), but
not motor implementation variability. These results are compatible
with the proposal that damage to the cerebellum slows the
acquisition of sensory and cognitive input, thereby disrupting a
wide variety of behaviors, especially those involving precise
timing.
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