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European Journal of Neuroscience 12 (supplement 11): 88 (abstract 44.8).
Effects of anterior cingulate cortex lesions on responding for conditioned
reinforcement, discrete fear conditioning, autoshaping performance and
Pavlovian–instrumental transfer
R.N. Cardinal, G. Lachenal, J.A. Parkinson (*), T.W. Robbins, B.J.
Everitt
Departments of Experimental Psychology and (*) Anatomy, University
of Cambridge, UK
The anterior cingulate cortex (Ant Cing) in the rat has previously been
shown to be critical for the acquisition of autoshaping, a measure of appetitive
Pavlovian conditioning in which animals come to approach a stimulus (CS+)
that predicts food delivery and not to approach a second stimulus (CS–)
that does not. Here we demonstrate that Ant Cing lesions do not impair
the acquisition of temporally discriminated approach to a CS that predicts
reward (US) and is located in the same place as the US. Lesioned animals
were able to respond instrumentally for this CS, now acting as a conditioned
reinforcer, and the potentiation of responding by intra-accumbens amphetamine
was unaffected. The Ant Cing-lesioned rats also acquired a freezing response
to a discrete CS paired with footshock at the same level as controls. However,
the same subjects were impaired at the acquisition of autoshaping, a task
involving two stimuli distinguishable only by spatial location and located
away from the source of food. A second group of Ant Cing-lesioned animals
were impaired on the performance of the autoshaping task when the lesions
were made after training to a criterion. These rats were tested on a Pavlovian-instrumental
transfer task, in which an appetitive CS potentiates instrumental responding
when it is presented non-contingently, and no impairment was found. These
results suggest that the Ant Cing is critical for the normal expression
of appetitive conditioning either when multiple stimuli must be discriminated,
or when the CS is spatially separate from the US; further work will aim
to clarify this.