HIV and chronic methamphetamine dependence affect cerebral blood flow.

Human immunodeficiency virus (HIV) and methamphetamine (METH) dependence are independently associated with neuronal dysfunction. The coupling between cerebral blood flow (CBF) and neuronal activity is the basis of many task-based functional neuroimaging techniques. We examined the interaction between HIV infection and a previous history of METH dependence on CBF within the lenticular nuclei (LN). Twenty-four HIV-/METH-, eight HIV-/METH+, 24 HIV+/METH-, and 15 HIV+/METH+ participants performed a finger tapping paradigm. A multiple regression analysis of covariance assessed associations and two-way interactions between CBF and HIV serostatus and/or previous history of METH dependence. HIV+ individuals had a trend towards a lower baseline CBF (-10%, p = 0.07) and greater CBF changes for the functional task (+32%, p = 0.01) than HIV- subjects. Individuals with a previous history of METH dependence had a lower baseline CBF (-16%, p = 0.007) and greater CBF changes for a functional task (+33%, p = 0.02). However, no interaction existed between HIV serostatus and previous history of METH dependence for either baseline CBF (p = 0.53) or CBF changes for a functional task (p = 0.10). In addition, CBF and volume in the LN were not correlated. A possible additive relationship could exist between HIV infection and a history of METH dependence on CBF with a previous history of METH dependence having a larger contribution. Abnormalities in CBF could serve as a surrogate measure for assessing the chronic effects of HIV and previous METH dependence on brain function.