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Procedural Learning among HIV+ and HIV- individuals with Substance Dependence. R. Gonzalez, J. Jacobus, J.W. Rodriguez, E.H. Fakhoury, E.M. Martin. Brief Background. HIV is associated with striatal damage Substance use affects striatal systems Striatum is critical for procedural learning
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Procedural Learning among HIV+ and HIV- individuals with Substance Dependence R. Gonzalez, J. Jacobus, J.W. Rodriguez, E.H. Fakhoury, E.M. Martin
Brief Background • HIV is associated with striatal damage • Substance use affects striatal systems • Striatum is critical for procedural learning • Procedural learning in HIV & substance use • A. Martin et al., (1993) • Kalechstein et al., (1998) • Van Gorp et al., (1999) • Waldrop et al., (2001)
Try to guess “sun” or “rain” based on cards Participants are not told probability structure 4 trial blocks, 50 cards each PL Measures Mirror Tracing (MT) Pursuit Rotor (PR) • Trace star seeing only mirror image • Go quickly, stay inside lines • 4 trial blocks, 2 trials each • DV = time to complete • Follow light around circle • 55 rpm • 4 trial blocks, 2 20s trials each • DV = seconds on target Weather Prediction (WP)
Performance Indices | General Deficit (Main Effect) | PL Deficit (Group X Time) | # Errors Performance on PL Tasks Control Group Learning Performance Clinical Group Time (Trial Blocks)
Hypotheses • HIV+ participants: • poorer performance, overall, on measures of PL • General Deficit • less improvement in performance over time on PL tasks • PL Deficit • More severe substance use: • poorer performance overall and with poorer PL • Interaction between HIV and substance use
Participants • 79 adults with history of cocaine and/or heroin dependence • HIV- : n = 33 • HIV+: n = 46 • Negative u-tox & alcohol breath test • No cocaine or heroin use in last 7 days • No current abuse or dependence for EtOH and other drugs • No history of severe thought disorder or unmedicated bipolar disorder • No history of significant loss of consciousness or neurological problems
Demographics Psychiatric & Medical
Summary of Results Mirror Tracing HIV Main Effect: HedgesES = 0.65, 95%CI [0.20, 1.11] Significant 3-way interactions
PR Interaction Effect HIV + HIV – PR change PR change KMSK KMSK n = 33 n = 46 R2 = .03, p = .24 R2 = .16, p = .02 ↑ improvement in PR was associated with history of ↑severe drug use [only for HIV- subjects]
MT Interaction Effect HIV + HIV – MT change MT change KMSK KMSK n = 33 n = 46 R2 = .03, p = .26 R2 = .12, p = .05 ↑ improvement in MT was associated with history of ↑severe drug use [only for HIV- subjects]
Summary • HIV+ subjects generally performed worse, overall, on PL tasks • Significant differences on Mirror Tracing • Evidence suggests general deficit • History of substance use severity and HIV serostatus interacted to affect procedural learning
Possible Explanations • Supersensitivity of striatal dopamine receptors • Process disrupted by HIV • HIV+ participants fairly “healthy” • Control group consisted of individuals with substance dependence • Amount of striatal damage not sufficient for functional deficits • HIV deficits are “spotty” affecting multiple systems
Acknowledgements • NIDA • F32 DA018522 (RG) • R01 DA12828 (EMM) • University of Illinois Chicago, Dept. of Psychiatry • HIV & Addictions Neuroscience • Eileen Martin, PhD • Jasmin Vassileva, PhD • Pyrai Vaughn • Elizabeth Walczak • Leslie Ladd • Sarah Wicks