Abstract
Neuroimaging data suggest that impaired performance on response inhibition and information processing tests in cocaine-dependent subjects is related to prefrontal and frontal cortical dysfunction and that dysfunction in these brain areas may underlie some aspects of cocaine addiction. In subjects with attention-deficit hyperactivity disorder and other psychiatric disorders, the Intra-Individual Reaction Time Variability (IIRTV) has been associated with frontal cortical dysfunction. In the present study, we evaluated IIRTV parameters in cocaine-dependent subjects vs. controls using a cocaine Stroop task. Fifty control and 123 cocaine-dependent subjects compiled from three studies completed a cocaine Stroop task. Standard deviation (SD) and coefficient of variation (CV) for reaction times (RT) were calculated for both trials with neutral and trials with cocaine-related words. The parameters mu, sigma, and tau were calculated using an ex-Gaussian analysis employed to characterize variability in RTs. The ex-Gaussian analysis divides the RTs into normal (mu, sigma) and exponential (tau) components. Using robust regression analysis, cocaine-dependent subjects showed greater SD, CV and Tau on trials with cocaine-related words compared to controls (p < 0.05). However, in trials with neutral words, there was no evidence of group differences in any IIRTV parameters (p > 0.05). The Wilcoxon matched-pairs signed-rank test showed that for cocaine-dependent subjects, both SD and tau were larger in trials with cocaine-related words than in trials with neutral words (p < 0.05). The observation that only cocaine-related words increased IIRTV in cocaine-dependent subjects suggests that cocaine-related stimuli might disrupt information processing subserved by prefrontal and frontal cortical circuits.
Original language | English (US) |
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Pages (from-to) | 193-197 |
Number of pages | 5 |
Journal | Addictive Behaviors |
Volume | 37 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2012 |
Keywords
- Cocaine Stroop task
- Cocaine dependence
- Ex-Gaussian analysis
- Intra-individual reaction time variability
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Clinical Psychology
- Toxicology
- Psychiatry and Mental health