| |
Abstract:
Based on research in experimental psychology we hypothesized
that dual-task related executive processes depend on the
requirements to coordinate interfering processing stages in two
tasks. Whether these processes draw on additional neuronal
resources compared to single tasks is still an open question. In an
fMRI investigation subjects had to perform two choice-reaction
tasks concurrently (dual-task), the single tasks and a resting
baseline. In experiment 1 dual-task specific activation was
investigated by analyzing additional activation in the dual-task
condition compared to both single-task conditions. The results
showed: Performing both tasks concurrently caused additional
bilateral activation in the lateral prefrontal cortex (cortical
areas along the inferior frontal sulcus - IFS) and in the superior
parietal lobe compared to both single-task conditions. A second
experiment tested whether this activation is caused by the
requirements to coordinate interfering processing stages. For that
purpose, temporal overlap between both tasks was manipulated
parametrically (three steps). An increased task overlap is expected
to be related to higher demands on executive processes because of
increased temporal overlap between interfering processing stages.
The behavioral results supported this hypothesis suggesting
increased dual-task costs due to increasing task overlap. The
neuroimaging results are discussed in terms of the assumption of a
prominent role of regions along the IFS for the coordination of
interfering processing stages in multitasking.
|
