Advanced Neuroimaging Evaluation of the Central Nervous System Biological Changes Associated With Efavirenz Therapy and Switch to an Elvitegravir-based Regimen

In this study we will use a multi-modal imaging approach of MRS and fMRI to comprehensively assess the biological changes in the brain associated with EFV-based regimen (EFV/FTC/TDF), specifically alterations in the brain circuitry, function and local neurochemistry, and their correlation with neuropsychological function. In a cohort of HIV-infected patients who are clinically stable on the commonly use regimen of EFV/emtricitabine (FTC)/truvada (TDF) or Atripla, we propose to replace the EFV component with a new integrase inhibitor, elvitegravir (EVG) boosted with cobicistat (COBI), given as the EVG/COBI/FTC/TDF Single Tablet Regimen (STR) to evaluate the EFV-related neural alterations. This is a multidisciplinary study which involves a team of infectious disease experts in the field of HIV, neuroradiologists with expertise in fMRI and MRS techniques to study various central nervous system and psychiatric disorders and a psychiatrist with experience and expertise in research on abnormalities of affective and motivational processing in the context of neuropsychiatric disorders. We will utilize the established clinical research platform in the Infectious Disease outpatient clinical practice at the Brigham and Women's Hospital, where there is currently have many ongoing HIV-related studies and a large panel of HIV-infected patients motivated to be involved in clinically relevant research. We propose to use advanced neuroimaging to measure biologically changes in the brain associated with long-term EFV use with the following specific aims: 1. Determine changes in neurometabolites measured by MRS in the brain associated with long-term EFV use 2. Assess for alterations in neural activity correlated with affective symptoms associated with EFV vs STR use using fMRI, and their associations with changes in neurometabolites assessed by MRS, and with changes in cognition assessed by Trail Making and Digit Substitution Tests. 3. Determine changes in emotion, cognition and slee