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Abstract:
Abstract: Functional neuroanatomy of time estimation has not
been well-documented. This research investigated fMRI measured
brain response to an explicit, prospective time interval production
(TIP) task. The study tested for presence of brain activity
reflecting a primary time keeper function, distinct from brain
systems involved in conscious strategies to monitor time or
attentional resource and other cognitive processes to accomplish
the task. In the TIP task, participants indicated when a given time
interval elapsed. Two control tasks (counting forwards, backwards)
were administered, plus a dual task format of the TIP task. Whole
brain images were collected at 1.5 Tesla. Analyses (n=6) yielded
SPM {z}'s reflecting time keeping and not strategy (counting,
number manipulation) or attention resource utilization. SPM {z}'s
involving accuracy and the magnitude of time estimation responses
were also conducted. Results revealed lateral cerebellar and
inferior temporal lobe activation were associated with primary time
keeping. Behavioral data demonstrated the time estimation
procedures did not occur automatically and utilized controlled
processes. Activation sites associated with accuracy, magnitude,
and the dual task provided indications of the other structures
involved in time estimation related to controlled processing. Data
are consistent with proposals that the cerebellum is a repository
of codes for time processing, and also implicate the temporal lobe
for this type of time estimation task.
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