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
Action-Outcome Contingency Degradation
Objective: Assess the effect of basolateral amygdala (BLA) lesions on instrumental conditioning in rats, specifically evaluating their ability to adjust performance when action-outcome contingency is degraded during training
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Equipment1
Not specified • Not specified • Not specified • Not specified
Materials2
Software1
Not specified • Not specified
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Protocol Steps
Surgical lesioning of basolateral amygdala
Lesions of the amygdala basolateral complex (BLA) were created in experimental animals; sham lesions performed on control animals
Note: Lesioned rats compared to sham controls throughout experiments
View evidence from paper
“we assessed the effect of lesions of the amygdala basolateral complex (BLA) on instrumental conditioning in rats”
Acquisition of instrumental actions
Rats trained to acquire lever pressing or chain pulling actions that earned either food pellets or maltodextrin solution as outcomes
Note: Testing conducted in food-deprived rats; lesion had no effect on acquisition
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 assessment
Sensory-specific satiety induced to devalue outcomes; instrumental performance assessed in extinction and when reward was contingent on performance
Note: Lesion attenuated the impact of outcome devaluation on instrumental performance
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
Action-outcome contingency was degraded during training; rats' ability to adjust performance appropriately was assessed
Note: Lesioned rats failed to adjust performance appropriately when contingency was degraded, differing from sham controls in encoding specific action-outcome contingencies
View evidence from paper
“lesioned rats failed to adjust their performance appropriately when the action-outcome contingency was degraded”
Discrimination of instrumental actions
Heterogeneous instrumental chain involving both lever pressing and chain pulling was used to assess whether lesioned rats could discriminate between two different instrumental actions
Note: Lesioned rats were similar to shams in acquisition of heterogeneous instrumental chain, indicating discrimination ability was intact
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 task
Rats tested in free operant discrimination situation to assess ability to use specific properties of instrumental outcomes to discriminate rewarded from unrewarded actions
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”