Altered neural reward and loss processing and prediction error signalling in depression

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Dysfunctional reward and punishment processing is implicated in depression.
• Previous functional magnetic resonance imaging (fMRI) studies show inconsistent results for reward processing in fronto-striatal regions.

Purpose of the Study:

• To investigate neural responsivity to reward and loss processing in depressed individuals.
• To examine prediction error (PE) signaling during incentive anticipation and receipt.
• To explore the relationship between neural activity and hedonic capacity in depression.

Main Methods:

• Thirty medication-free depressed individuals and 28 healthy controls underwent fMRI while performing a reward paradigm.
• Region of interest analyses focused on neural responses during anticipation and receipt of gains/losses and PE signals.
• Assessed the correlation between neural responsivity and hedonic capacity.

Main Results:

• Depressed individuals exhibited reduced fronto-striatal activity during anticipation of gains and losses compared to controls.
• No significant group differences were observed in response to reward and loss outcomes.
• Increased orbitofrontal cortex and nucleus accumbens activity during reward anticipation correlated with hedonic capacity in depressed individuals.
• Depressed individuals showed absent reward-related PEs but encoded loss-related PEs in the ventral striatum.

Conclusions:

• Depression is associated with blunted fronto-striatal responsivity, potentially leading to diminished motivational responses to rewards and losses.
• Altered prediction error encoding in depression may reflect blunted reward and enhanced loss-related associative learning.