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Abstract:
In our daily lives we constantly, rapidly and unintentionally
acquire new arbitrary visuomotor associations. In the present PET
experiment we investigated the neuronal correlates of learning such
arbitrary visuomotor associations using a mapping paradigm similar
to the paradigms used in automaticity studies. In our mapping task
subjects had to respond to three abstract figures by pressing three
buttons. Each mapping task consisted of 50 trials and was repeated
four times. Before each task the appropriate stimulus-response
associations were indicated. Associations remained unchanged
throughout repetitions of the consistent mapping task, whereas they
changed for each repetition of the varied mapping task. Subjects
were not informed that the mapping rules differed between the
tasks. We measured the response times and rCBF (using H2O15) in
eight volunteers while they performed the mapping tasks and four
rests. Response speed significantly improved in both mapping tasks,
but improvements occurred earlier and were more important in the
consistent mapping task. Moreover, learning the visuomotor
associations increased the rCBF in the left precentral (Z = 2.64)
and postcentral gyri (Z = 2.61), but decreased neuronal activity in
the right lingual (Z = 2.81) and middle fusiform gyri (Z = 2.52).
These findings suggest that the rapid and unintended learning of
visuomotor associations modulates neuronal activity in visual as
well as in motor regions.
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