Source Paper
Dissociation in Effects of Lesions of the Nucleus Accumbens Core and Shell on Appetitive Pavlovian Approach Behavior and the Potentiation of Conditioned Reinforcement and Locomotor Activity byd-Amphetamine
John A. Parkinson, Mary C. Olmstead, Lindsay H. Burns, Trevor W. Robbins, Barry J. Everitt
Journal of Neuroscience • 1999
Pavlovian Conditioning and CS-US Association
Objective: To investigate the functional dissociation of nucleus accumbens (NAcc) core and shell subregions in mediating Pavlovian CS-US associations, conditioned reinforcement, and amphetamine-potentiated behavioral responses
Gather these items before starting the experiment. Check off items as you prepare.
Equipment2
Not specified • Not specified • Not specified • Not mentioned
Not specified • Not specified • Not specified • Not mentioned
Materials2
Not specified • Not specified • Not specified • Not mentioned
Not specified • Not specified • Not specified • Not mentioned
Software1
Not specified • Not mentioned
As an Amazon Associate, we earn from qualifying purchases. Product links help support this free resource.
Protocol Steps
Initial Pavlovian CS-US Association Training
Rats were trained to associate a neutral stimulus (Pavlovian CS) with food reinforcement (US) to establish baseline Pavlovian associations
Note: This is the initial training phase before lesion surgery
View evidence from paper
“Rats were initially trained to associate a neutral stimulus (Pavlovian CS) with food reinforcement (US)”
Excitotoxic Lesion Surgery
Excitotoxic lesions were performed to selectively destroy either the nucleus accumbens core or shell in separate groups of animals
Note: Two lesion groups: NAcc core-lesioned and NAcc shell-lesioned animals
View evidence from paper
“After excitotoxic lesions that selectively destroyed either the NAcc core or shell”
Post-Lesion CS-US Retraining Sessions
After lesion recovery, animals underwent additional CS-US training sessions to assess Pavlovian conditioning following selective NAcc subregion damage
Note: Core-lesioned animals showed impairment during these sessions; shell-lesioned animals showed no deficit
View evidence from paper
“After excitotoxic lesions that selectively destroyed either the NAcc core or shell, animals underwent additional CS–US training sessions”
Instrumental Conditioning with Conditioned Reinforcer
Animals were tested for acquisition of a new instrumental response (lever pressing) that produced the CS acting as a conditioned reinforcer (CR). Testing involved both a CR lever (reinforced with CS presentation) and a control lever (non-reinforced)
Note: Measures ability to learn new instrumental response using previously conditioned stimulus as reinforcer
View evidence from paper
“animals underwent additional CS–US training sessions and then were tested for the acquisition of a new instrumental response that produced the CS acting as a conditioned reinforcer (CR)”
Intra-NAcc Amphetamine Infusion During Testing
During each instrumental conditioning session, animals were infused intra-NAcc with d-amphetamine at varying doses (0, 1, 3, 10, or 20 μg) before the session to test dose-dependent potentiation of conditioned reinforcement and locomotor activity
Note: Dose-response design with five amphetamine dose levels including vehicle control (0 μg)
View evidence from paper
“Animals were infused intra-NAcc with d-amphetamine (0, 1, 3, 10, or 20 μg) before each session”
Measurement of Behavioral Responses
During testing sessions, measure responding on the CR lever (reinforced with conditioned stimulus presentation), responding on the control non-reinforced lever, and locomotor activity
Note: Selective potentiation of CR lever responding indicates intact shell function; increased responding on both levers indicates core lesion-induced deficit in selectivity
View evidence from paper
“the selectivity in stimulant-induced potentiation of the CR lever was reduced, as intra-NAcc amphetamine infusions dose-dependently increased responding on both the CR lever and a nonreinforced (control) lever”