Incentive memory: Evidence the basolateral amygdala encodes and the insular cortex retrieves outcome values to guide choice between goal-directed actions
Journal of Neuroscience. 2013-05-15; 33(20): 8753-8763
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1. J Neurosci. 2013 May 15;33(20):8753-63. doi: 10.1523/JNEUROSCI.5071-12.2013.
Incentive memory: evidence the basolateral amygdala encodes and the insular
cortex retrieves outcome values to guide choice between goal-directed actions.
Parkes SL(1), Balleine BW.
(1)Brain and Mind Research Institute, University of Sydney, Camperdown, New South
Wales 2050, Australia.
Choice between goal-directed actions is determined by the relative value of their
consequences. Such values are encoded during incentive learning and later
retrieved to guide performance. Although the basolateral amygdala (BLA) and the
gustatory region of insular cortex (IC) have been implicated in these processes,
their relative contribution is still a matter of debate. Here we assessed whether
these structures interact during incentive learning and retrieval to guide
choice. In these experiments, rats were trained on two actions for distinct
outcomes after which one of the two outcomes was devalued by specific satiety
immediately before a choice extinction test. We first confirmed that, relative to
appropriate controls, outcome devaluation recruited both the BLA and IC based on
activation of the immediate early gene Arc; however, we found that infusion of
the NMDAr antagonist ifenprodil into the BLA only abolished outcome devaluation
when given before devaluation. In contrast, ifenprodil infusion into the IC was
effective whether made before devaluation or test. We hypothesized that the BLA
encodes and the IC retrieves incentive value for choice and, to test this,
developed a novel sequential disconnection procedure. Blocking NMDAr activation
unilaterally in the BLA before devaluation and then contralaterally in the IC
before test abolished selective devaluation. In contrast, reversing the order of
these infusions left devaluation intact. These results confirm that the BLA and
IC form a circuit mediating the encoding and retrieval of outcome values, with
the BLA encoding and the IC retrieving such values to guide choice.
PMID: 23678118 [Indexed for MEDLINE]