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Abstract:
Using PET we studied brain responses to predictable sensory
events and to similar unpredictable events and especially how the
processing of predictable sensory events is modified by the context
of a causative self-generated action. Increases in activity when
sensory stimuli (tones) were unpredictable were seen in the
inferior and superior temporal lobe bilaterally, the right
parahippocampal gyrus and right parietal cortex. Self-generated
actions produced activity in a number of motor and premotor areas,
including dorsolateral prefrontal cortex. We observed an
interaction between the predictability of stimuli and
self-generated actions in several areas, including the medial
posterior cingulate cortex, left insula, dorsomedial thalamus,
superior colliculus and right inferior temporal cortex. This
modulation of activity associated with stimulus predictability in
the context of self-generated actions implies that these areas may
be involved in selfmonitoring processes. We conclude that detection
of expected stimuli and the detection of the sensory consequences
of self-generated actions appear to be functionally distinct
processes, and are carried out in different cortical areas.
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