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Abstract:
Recent neuropsychological studies have identified the Stroop
Test as a sensitive marker of CNS involvement in patients with HIV
infection (Hinkin, 2000). Several neuroimaging studies of healthy
individuals have shown activity in dorsal anterior cingulate cortex
(DAC) during Stroop and Stroop-like tasks (Bush et al., 1998). In
this study, we used the Counting Stroop (Bush, 1998) and the
Oddball Stroop, fMRI-compatible modifications of the Stroop task,
to examine DAC function in 7 high-functioning HIV-infected
individuals and 3 age-matched control subjects. The purpose of the
study was to determine whether HIV-positive subjects who perform
comparably to control subjects have similar patterns of activation
in the DAC, or whether changes in activation precede declines in
reaction time or accuracy. All subjects demonstrated a Stroop
interference effect and while HIV-positive subjects evidenced a
greater effect compared to control subjects, this was not
statistically significant. Preliminary analysis of fMRI data (1.5T
Siemens scanner, EPI, SPM) revealed DAC activity in 7/7 subjects
(Counting Stroop) and in 6/7 subjects (Oddball Stroop). These data
suggest that while Stroop tasks may be sensitive to CNS changes in
HIV-infected persons, those who perform comparably to HIV-negative
peers do not necessarily show functional changes in the DAC region.
Supported by NIH NS40239, NIMH01611, NARSAD.
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