Publication Abstract Display | Type: Published Abstract | Title: Visuospatial attention and methamphetamine dependence: Increased regional fMRI activation and response latency. | Authors: Jacobson MW, Archibald SL, Grant I, Jernigan TL, and the HNRC Group | Year: 2005 | Publication: Journal of the International Neuropsychological Society | Volume: 11 Issue: Suppl S1 Pages: 181 | Abstract:To use a visual attention paradigm and functional neuroimaging to iden-
tify methamphetamine-related changes in 1)fMRI activation patterns in
striatal and parietal regions, and 2)response latency in spatial attention
shifting. Participants were 7 methamphetamine dependent adults
(METH+ group) and 6 matched controls. The visual attention-shifting
paradigm uses numbers constructed from global/local Navon-type fig-
ures. Using a response box, the subject identifies targets numbers (1 -
4) among distractors (5-9) appearing at either the global or local level
in directed and divided attention conditions. FMRI results for whole-
brain cluster analysis: the METH+ group had increased blood oxy-
genation level dependent (BOLD)changes in response to the divided at-
tention condition (p < .05), especially in thalamus, inferior and superior
parietal and occipital lobes compared to controls. Behavioral data indi-
cated that the METH+ group had significantly longer response latency
in both directed and divided attention conditions (814 & 975 msec)
compared to controls (623 msec & 746 msec respectively). Increased
FMRI BOLD response in the METH+ group suggests a possible com-
pensatory mechanism in neural regions supporting visuospatial atten-
tion. Behavioral data indicate deficits in spatial attention-shifting, largely
the result of increased latency when the switching response required in-
hibition of prepotent global targets. These preliminary findings are con-
sistent with recent studies noting brain structure/function alterations
resulting from METH-related damage and neurotransmitter dysregu-
lation. Behavioral data are consistent with inhibition, learning and at-
tentional shifting deficits previously noted in this group. |
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