Source Paper
The Effect of Lesions of the Basolateral Amygdala on Instrumental Conditioning
Bernard W. Balleine, A. Simon Killcross, Anthony Dickinson
Journal of Neuroscience • 2003
Free Operant Discrimination
Objective: Evaluation of rats' ability to use specific properties of instrumental outcomes to discriminate rewarded from unrewarded actions in a free operant situation
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Equipment1
Not specified • Not specified • Not specified • Not specified
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Protocol Steps
Surgical lesion of basolateral amygdala
Rats received lesions of the amygdala basolateral complex (BLA) or sham surgery
Note: Lesioned and sham control groups were compared
View evidence from paper
“we assessed the effect of lesions of the amygdala basolateral complex (BLA) on instrumental conditioning in rats”
Instrumental action acquisition training
Food-deprived rats trained to perform lever pressing or chain pulling actions that earned either food pellets or maltodextrin solution
Note: Both lesioned and sham rats were trained on these actions
View evidence from paper
“the lesion had no effect on the acquisition of either lever pressing or chain pulling in food-deprived rats whether these actions earned food pellets or a maltodextrin solution”
Outcome devaluation test
Sensory-specific satiety was induced to devalue the instrumental outcome, and performance was assessed in extinction and with contingent reward delivery
Note: Lesioned rats showed attenuated impact of outcome devaluation compared to shams
View evidence from paper
“The lesion did attenuate, however, the impact of outcome devaluation, induced by sensory-specific satiety, on instrumental performance both when assessed in extinction and when reward was delivered contingent on instrumental performance”
Action-outcome contingency degradation test
The action-outcome contingency was degraded during performance to assess encoding of specific contingencies
Note: Lesioned rats failed to adjust performance appropriately when contingency was degraded
View evidence from paper
“lesioned rats failed to adjust their performance appropriately when the action-outcome contingency was degraded”
Heterogeneous instrumental chain training
Rats trained on a heterogeneous instrumental chain involving both lever pressing and chain pulling to assess discrimination ability between actions
Note: Lesioned and sham rats showed similar acquisition, indicating no deficit in action discrimination
View evidence from paper
“these rats were similar to shams in their acquisition of a heterogeneous instrumental chain involving lever pressing and chain pulling”
Free operant discrimination test
Rats tested on their ability to use specific properties of instrumental outcomes to discriminate rewarded from unrewarded actions in a free operant discrimination situation
Note: BLA lesions produced a deficit in this discrimination ability
View evidence from paper
“lesions of the BLA were found to produce a deficit in the ability of rats to use the specific properties of the instrumental outcomes used in the previous experiments to discriminate rewarded from unrewarded actions in a free operant discrimination situation”