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@PHDTHESIS{Vohn:49969,
author = {Vohn, René},
othercontributors = {Spijkers, Wilhelmus},
title = {{F}unctional networks of within- and cross-modal divided
attention},
address = {Aachen},
publisher = {Publikationsserver der RWTH Aachen University},
reportid = {RWTH-CONV-112536},
pages = {93 Bl. : Ill., graph. Darst.},
year = {2008},
note = {Zusammenfassung in dt. und engl. Sprache; Aachen, Techn.
Hochsch., Diss., 2008},
abstract = {In modern neuropsychology attention is subdivided into
different domains (Fernandez-Duque $\&$ Posner, 2001; Posner
$\&$ Boies, 1971; Posner $\&$ Rafal, 1987; Sturm, 2005; van
Zomeren $\&$ Brouwer, 1994). One of these domains is divided
attention, which describes the ability to process two or
more different tasks at the same time. According to
Wickens´ (1984) multiple resources theory, processing two
tasks simultaneously presented in the same sensory modality
(within-modal) is more difficult than processing two tasks
presented in two different sensory modalities (cross-modal).
Furthermore, many experimental studies demonstrated
age-related differences in different divided attention tasks
(Brouwer et al., 1991; Levitt et al., 2006; Ponds et al.,
1988; McDowd $\&$ Craik, 1988; Somberg $\&$ Salthouse, 1982;
Coburn et al., 2006). Compared with young adults, older
adults showed a significantly decreased ability to divide
attention. Modern functional imaging techniques such as
functional magnetic resonance imaging (fMRI) provide the
opportunity to identify brain structures which are linked to
known psychological processes and effects. This thesis
describes two different fMRI-experiments dealing with the
execution of divided attention tasks. In the first
experiment, we were interested in distinguishing the
cortical representations of within-modal and cross-modal
divided attention tasks. Sixteen healthy male subjects aged
between 21 and 30 years underwent two within-modal
(auditory/auditory, visual/visual) and one cross-modal
(auditory/visual) divided attention task, as well as related
selective attention control conditions. After subtraction of
the corresponding control tasks the three divided attention
tasks, irrespective of sensory modality, revealed
significant activation in a right hemisphere network
involving the prefrontal cortex, the inferior parietal
cortex and the claustrum. Under the cross-modal condition,
however, the frontal and parietal activation was more
extended and more bilateral and there was also stronger
right hemisphere activation of the anterior cingulate gyrus
and the thalamus. In comparison to the within-modal
conditions additional bilateral frontal and left inferior
parietal activation was found for the cross-modal one. The
supplementary fronto-parietal, anterior cingulate gyrus and
thalamus activation in the auditory/visual condition could
be argued to reflect an additional demand for coordination
of two ongoing cross-modal cognitive processes. In the
second fMRI-experiment, we were interested in detecting
aging effects possibly causing age-related differences in
cortical representations of within-modal and cross-modal
divided attention tasks. A young group (aged 21 to 39 years)
and an old group (aged 51 to 74 years) each comprising
sixteen healthy male subjects underwent one cross-modal
(auditory/visual) and two within-modal (auditory/auditory;
visual/visual) divided attention tasks like in the first
experiment. During the cross-modal task, the old group
revealed stronger divided attention specific bilateral
activation in inferior and middle frontal areas, in the
cingulate gyrus and in the inferior parietal lobule as well
as in the left claustrum than the young group. In the old
group the right inferior parietal lobule was also stronger
activated while performing the two within-modal tasks,
indicating that in older people this specific brain
structure is highly involved in divided attention
irrespective of sensory modality. We assume that the
described additional activation in the old group reflects
compensatory effects caused by the greater demand for
attentional resources in order to regulate the system. On
the other hand, the young group only showed additional
activation in the thalamus during the cross-modal task. This
might represent a more bottom-up organized processing of
divided attention tasks.},
keywords = {Aufmerksamkeit (SWD) / NMR-Tomographie (SWD) /
Neuropsychologie (SWD) / Altersunterschied (SWD) /
Alterspsychologie (SWD)},
cin = {721520},
ddc = {150},
cid = {$I:(DE-82)721520_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-opus-22139},
url = {https://publications.rwth-aachen.de/record/49969},
}
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