Altered hedonic capacity is considered to be vulnerability marker that precedes the onset of neuropsychiatric disorders and may be the result of neurophysiological dysfunction. Recent studies showed that this kind of altered hedonic capacity, usually in form of a reduced capacity known as anhedonia, is also observed in non-clinical sample as a behavioral manifestation of an enduring trait.

Previous studies on anhedonia in both clinical and non-clinical samples primarily focused on monetary rewards rather than affective and social rewards. It is still unclear whether the underlying neural mechanisms of the monetary-based and affect-based anhedonia have distinct neural mechanisms.

Dr. CHAN Raymond's team from the Institute of Psychology of Chinese Academy of Sciences has shown that individuals with social anhedonia exhibited a domain-specific deficit towards social affective information but not towards monetary-based rewards. The findings suggested that incentive type could confound the findings on the dissociation of anticipatory and consummatory hedonic capacities.

Based on these findings, Dr. CHAN's team conducted a study to examine the neural mechanisms of monetary-based and affective-based hedonic capacity in individuals with social anhedonia. They administered the Affective Incentive Delay (AID) and the Monetary Incentive Delay (MID) imaging tasks to 28 adolescent participants. A cue signaling the type of forthcoming feedback (reward or punishment) was displayed to the participants, followed by a target-hit task with corresponding reward or punishment.

The study showed that the striatal and limbic regions were activated during the anticipatory phase of MID, while there was no brain activation during the anticipatory phase of AID. In the consummatory phase, the MID task activated the medial frontal cortex, while the AID task activated the frontal and dorsal limbic regions. In a subsequent subtype analysis, the researchers found that individuals with social anhedonia exhibited significant hypoactivation than those without social anhedonia at the left pulvinar, the left claustrum and the left insula to positive cuesin the anticipatory phase of the AID task.

It is the first study that examines functional brain responses to affective and monetary incentives in individuals with and without anhedonia. The findings demonstrate that the AID and the MID tasks have unique activation patterns and the AID task may be more sensitive in detecting anhedonia in individuals with trait anhedonia.

The study was supported by the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences, the National Science Fund China, and the Beijing Training Project for Leading Talents in S&T. The paper is available in Neuropsychology.