Disconnection of the entorhinal cortex and the dorsomedial striatum impairs the sensitivity to instrumental contingency degradation

Bjoern Lex (1) , Wolfgang Hauber (1)

1 Department of Animal Physiology

The capacity to detect changes in the causal efficacy of actions is mediated by a number of brain areas including the entorhinal cortex (EC) and the posterior part of the dorsomedial striatum (pDMS). Here, we examined whether interactions between the EC and the pDMS are required to detect changes of the instrumental contingency. Rats that received EC-pDMS disconnection lesions, i.e. unilateral cell body lesions of the EC and contralateral dopamine depletions of the pDMS, were trained to press two levers, one delivering food pellets, the other a sucrose solution. Thereafter, we tested whether rats were sensitive (i) to a selective devaluation of the value of one of two outcomes using a specific satiety procedure, and (ii) to a selective degradation of one of two contingencies controlling instrumental choice behavior. Our results reveal that rats with EC-pDMS disconnection lesions were sensitive to outcome devaluation. However, unlike rats with sham lesions or unilateral EC and pDMS lesions, rats with EC-pDMS disconnection lesions showed a reduced sensitivity to contingency degradation. These findings suggest that the EC and the pDMS may be part of a neural system that supports the detection of changes in the causal relationship between an action and its consequences.

Mots clés: Animal models; Behavioral Science; Learning & Memory; Cognition; Entorhinal Cortex; Posterior Dorsomedial Striatum; Instrumental Conditioning; Rat; Dopamine

Bjoern Lex, Wolfgang Hauber. Disconnection of the entorhinal cortex and the dorsomedial striatum impairs the sensitivity to instrumental contingency degradation. Neuropsychopharmacology, 2010, ⟨10.1038/npp.2010.46⟩. ⟨hal-00522560⟩