Dissociating motivation from reward in human striatal activity

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Striatal neural activity typically correlates with anticipated reward value.
• Previous research often conflates reward value with the motivation to seek rewards.
• Understanding distinct neural signals for value and motivation is crucial for deciphering reward processing.

Purpose of the Study:

• To dissociate neural signals related to expected reward value from those related to motivation within the striatum.
• To investigate regional differences in striatal responses to value and motivation using functional magnetic resonance imaging (fMRI).

Main Methods:

• Utilized a novel task design where motivation increased as anticipated reward decreased, reversing the typical relationship.
• Employed fMRI to measure blood-oxygen-level-dependent (BOLD) responses in the striatum.
• Collected self-report ratings for arousal and liking to correlate with neural activity.

Main Results:

• Striatal activity differentially scaled with expected value and motivation.
• Nucleus accumbens activity positively correlated with expected reward value.
• Caudate and putamen activity increased with motivation and were associated with arousal, unlike nucleus accumbens associated with liking.

Conclusions:

• Striatal activation patterns are not uniform; distinct subregions process reward value and motivation.
• Nucleus accumbens activity is more closely linked to reward 'liking' or experienced value.
• Caudate and putamen activity are more associated with motivation and arousal, highlighting regional specificity in reward processing.