Nucleus accumbens core and shell inactivation differentially affects impulsive behaviours in rats

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Neurobiology

Background:

• Impulsivity is complex, involving decision-making and action control deficits.
• Subcortical regions, particularly the nucleus accumbens (NAc), modulate impulsive behavior.
• The NAc has distinct core and shell subregions potentially involved in different aspects of impulsivity.

Purpose of the Study:

• To investigate the specific roles of the NAc core and shell in impulsive choice and impulse control.
• To differentiate the contributions of NAc subregions to various facets of impulsivity.

Main Methods:

• Reversible inactivation of rat NAc core and shell using muscimol, a GABAA receptor agonist.
• Behavioral assessment using a 5-choice serial reaction time task (5-CSRTT) for impulse control and a T-maze task for impulsive choice.
• Administration of muscimol and fluorophore-conjugated muscimol (FCM) to assess effects on behavior.

Main Results:

• Inactivation of both NAc core and shell increased impulsive choice, impairing waiting capacity.
• NAc shell inactivation specifically worsened impulse control in the 5-CSRTT.
• NAc core deactivation led to general task performance deficits, suggesting motivational/motor roles.

Conclusions:

• The NAc shell is clearly implicated in both impulsive choice and impulse control.
• NAc subregions exhibit functional dichotomy: shell in both impulsivity types, core in motivational/motor aspects of impulse control.
• Findings highlight the distinct roles of NAc core and shell in regulating impulsive behaviors.