 Primary aims are to evaluate whether 1 corticostriatal function during reward motivation and anticipation are associated with change in peripheral inflammation following pharmacologic blockade relative to placebo 2 the temporal dynamics of change in inflammation, gene- expression, reward motivation and reinforcement learning behavior and motivational symptoms assessed at baseline, and 24 hours, 3 days, 1 week and two weeks post infliximab infusion, and 3 test an integrative multi- level path model to determine whether change in corticostriatal circuitry following inflammation blockade mediates the relationship between change in inflammation and change in motivational anhedonia symptoms. 