Nucleus accumbens responses differentiate execution and restraint in reward-directed behavior

Area of Science:

• Neuroscience
• Behavioral Science

Background:

• Environmental cues powerfully influence behavior by signaling reward availability.
• Impulsive behavior, characterized by an inability to restrain actions toward rewards, is linked to maladaptive behaviors like substance abuse and overeating.
• The nucleus accumbens (NAc) integrates cognitive and affective inputs to influence action through basal ganglia outputs.

Purpose of the Study:

• To investigate whether nucleus accumbens (NAc) neuronal signals relate more to reward prediction or behavioral response selection.
• To dissociate the roles of NAc neurons in processing reward cues versus initiating actions.

Main Methods:

• Recorded the activity of NAc neurons in rats performing a task with distinct cues.
• Rats were trained on a task where cues indicated reward availability, requiring either a lever press (Go) or withholding the press (NoGo).

Main Results:

• Individual cue-responsive NAc neurons exhibited either increased or decreased activity at cue onset.
• These cue responses were larger (increases) or smaller (decreases) when rats withheld lever pressing, irrespective of trial type (Go or NoGo) or accuracy.
• NAc cue responses correlated with the motor action (pressing or withholding), not solely with the predictive value of the cue.

Conclusions:

• Nucleus accumbens (NAc) cue responses are associated with behavioral action selection, not just reward prediction.
• These findings suggest a critical role for the NAc in mediating the action-driving effects of reward-associated cues.
• Understanding NAc function in action control may offer insights into impulsive behaviors and addiction.