Inefficient integration between effort and reward in anhedonia

Anhedonia is defined as a reduced interest in or inability to experience pleasure from reward-related activities. Recent studies have demonstrated deficient effort-based motivation in anhedonia, but the neural dynamics underlying the interface between effort and reward remain unclear.

To address this issue, we recruited an anhedonia (ANH) group (N = 40) and a control (CNT) group (N = 40) to complete two tasks: (1) an effort-reward task where participants earned varying rewards by exerting different levels of physical effort and (2) an effort-based decision-making task where they chose between a no-effort option for a smaller reward and a high-effort option for a larger reward. We recorded EEG during both tasks and analyzed the resulting neural responses.

As expected, the ANH group showed reduced reward responses in both self-reported ratings and event-related potential (ERP) data in response to cue stimuli (indexed by the cue-P3) and reward feedback (indexed by the reward positivity). Importantly, the ANH group exhibited inefficient integration between effort and reward, showing an absent effort-discounting effect on the feedback-P3 during reward evaluation and a lack of reward-related theta modulation during effort-based decision-making.

Our findings suggest a neurodynamic motivation model in anhedonia that informs precise interventions for relevant neuropsychiatric disorders.