Project neuroARTEMIS

Functional connectivity (FC) will be derived from the the resting-state functional MRI data. Using a theory-driven, seed-based approach, the 4D time series [average blood oxygenation level dependent (BOLD) signal across voxels] will be extracted from a priori seeds in the reward network (i.e., nucleus accumbens, subgenual anterior cingulate cortex, medial orbitofrontal cortex). Normalized Z-scores will be calculated for FC between regions of interest. These analyses will control for baseline FC.

The Monetary Incentive Delay Task will be used to probe neural activation to reward processing, using an event-level design. Blood oxygenation level dependent (BOLD) activation will be modeled as a canonical hemodynamic response function specified at stimulus onset. Event epochs that are time locked to the onset of each trial will be extracted from the overall time series. Random-effects general linear model will be used to calculate statistical parametric maps reflecting the probability that a voxel is activated as a function of the experimental task. The primary analysis will focus on nucleus accumbens and ventromedial prefrontal cortex activity as regions of interest (ROI). Mean beta values will be averaged across all voxels in each ROI. These analyses will control for baseline activation levels.

Utilizing a Timeline Follow-back, days of stimulant use in past 30 will be assessed. Stimulants will include methamphetamine, other amphetamines, cocaine, and other stimulants. Change in use from baseline will be examined.

Depression symptom severity, measured via (CES) Center for Epidemiologic Studies Depression Scale. This assessment is a 20 item assessment with each item being assigned a value of 0-3. Higher scores are indicative of depression. The total score is calculated by calculating the sum of 20 items. Scores range from 0-60, with higher scores meaning greater depressive symptoms. We will examine change from baseline.

RNA sequencing (RNAseq) of peripheral blood mononuclear cells (PBMCs) will be conducted for analysis of differential gene expression, detection of low expressed genes, allele specific expression analysis, and splice variants. Gene expression values will be log2-transformed and pre-specified sets of inflammatory and Type I interferon genes will be combined into a single-number CTRA indicator (53-gene contrast score).

Plasma samples will undergo multiplexed analysis for key inflammatory mediators: CRP, TNF-a, IFN-g, IL-1b, IL-6, CXCL10, and CCL2. Single-enzyme-linked immunoabsorbent assays (ELISAs) will be performed for sCD14 and sCD163. We will examine changes in concentration from baseline.