101. Peripheral inflammation impairs motivation through modulation of fundamental gain and loss associated prediction error signals in ventral striatum and anterior insula

Abstract

Inflammation reduces reward-seeking behaviour and increases avoidance of aversive stimuli. However, how this is neurally mediated remains unclear. Here we addressed this using a Typhoid vaccine experimental inflammation model together with computational modelling of an instrumental learning task performed during fMRI (1). Twenty-two healthy participants were each tested 3-h after blindly administered typhoid vaccine (0.025 mg) and placebo (0.5 ml 0.9% NaCl) injection. Typhoid but not placebo was associated with a threefold increase in plasma IL-6 ( t (21) = 5.20, p F (21,1) = 6.41, p = 0.019. Computational modelling of individuals’ choices using a Q-learning model (free parameters alpha (learning-rate), beta (choice-randomness) and R (reward value)) demonstrated significant reduction in reward cue value and increase in value of punishment cues following inflammation F (21,1) = 3.63, p p p