Publication Abstract Display
Type: Published Abstract
Title: Increased motor complexity evokes increased caudate activation despite lower response rate in HIV.
Authors: Fennema-Notestine C, Archibald SL, Fine EM, Grant I, Jernigan TL
Year: 2001
Publication: Society for Neuroscience Abstracts
Volume: 27 Issue: Pages: 235
Abstract:FMRI may be capable of detecting early HIV-related effects in the basal ganglia, such as motor and psychomotor slowing. We administered a responsive motor switching (RMS) paradigm to 8 HIV- and 6 HIV+ subjects. In the RMS periods, which alternated with rest, subjects switched between three motor tasks every few seconds. These tasks increased in complexity: simple finger tapping, finger sequencing (SEQ), and alternating finger tapping (ALT). The HIV+ group made significantly fewer responses, but did not differ on accuracy measures from the HIV- group. In whole-brain voxel-by-voxel analyses, BOLD signals were correlated with reference functions contrasting motor switching with rest and directly comparing the specific motor tasks. Motor switching evoked robust increases in basal ganglia activation within both groups, although there were few differences between the groups and none in basal ganglia. Coding the three tasks linearly for increasing complexity revealed significantly more "complexity-related" activation in the HIV+ subjects than in controls in dorsal parts of the head of the caudate nucleus; HIV+ subjects showed increased caudate activation for more complex tasks, despite fewer responses. In the task specific contrasts, the SEQ and ALT comparison revealed the strongest complexity effect. These results suggest that this method may be capable of revealing dysfunction in particular brain structures in patients with HIV-related motor impairments.

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