Instrumental successive negative contrast in rats: Preliminary studies on the role of prefrontal cortex.

KLIGER, R., PAPINI, M. R. & MUZIO, R. N.

Huerta Grande, Córdoba

Congreso; XXVIII Congreso de la Sociedad Argentina de Investigación en Neurociencia (SAN); 2013

Sociedad Argentina de Investigación en Neurociencia (SAN)

When animals trained to receive a large reward experience a surprising decrease in reward magnitude, their performance deteriorates below the level of a control group always exposed to the small reward magnitude. This phenomenon, called successive negative contrast (SNC) has been found in both consummatory (cSNC) and instrumental (iSNC) procedures. There is behavioral and neural evidence that their underlying mechanisms are different. However, whereas there is evidence that prefrontal cortex areas, such as the anterior cingulated and the insular cortex, are involved in cSNC, no such cortical involvement has been reported for iSNC. We present results of a behavioral procedure developed to study the role of prefrontal cortex on iSNC via lesion and cell activity procedures. Two groups of rats received one trial per day in a runway situation rewarded with 32 pellets for either 12 or 24 daily trials. Thereafter, they were downshifted to 4 pellets for an additional 10 trials. Their runway performance deteriorated relative to a group that always received 4 pellets. Advantages of this procedure will be discussed in relation to ongoing experiments that explore the role of prefrontal areas in iSNC.