Learning to like: a role for human orbitofrontal cortex in conditioned reward.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• Human motivation relies on emotional significance of events and learned associations.
• Previous research links ventral striatum, orbitofrontal cortex (OFC), and amygdala to reward processing and anticipation.
• Investigating conditioned reward without explicit anticipation is crucial for understanding complex value representation.

Purpose of the Study:

• To compare brain activation during direct reward presentation versus conditioned reward stimuli.
• To investigate the role of the orbitofrontal cortex (OFC) in representing conditioned reward value.
• To explore conditioned reward in the absence of explicit reward anticipation.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used on 22 healthy volunteers.
• Visual patterns were incidentally associated with reward or negative feedback during a card game.
• Brain activation was assessed during initial conditioning and a subsequent passive viewing session.

Main Results:

• Reward versus negative feedback activated the ventral striatum and OFC.
• The OFC showed activation when viewing previously reward-associated stimuli, without explicit reward.
• Behavioral assessment confirmed the affective valence of conditioned stimuli.

Conclusions:

• The orbitofrontal cortex (OFC) is crucial for representing both direct rewarding stimuli and conditioned stimuli with acquired reward value.
• Findings suggest the OFC's role extends to representing learned reward associations, independent of immediate reward anticipation.
• This study highlights the neural mechanisms underlying how environmental cues acquire emotional and motivational significance.