Profiles of animals exposed to an incentive downshift

ANNICCHIARICO, I.; CUENYA, L.

San Diego

Congreso; 46th Annual Neuroscience Metting; 2016

Society of Neuroscience

Consummatory Successive Negative Contrast (cSNC) is one of the phenomenon most commonly observed when animals are confronted to an incentive downshift. It occurs when animals having an exposure to an unexpected downshift, from a high palatable reward (e.g., 32% sucrose solution) to a less preferred one (e.g., 4% sucrose solution), show an abrupt and transient suppression of the consummatory response. Control animals that have always access to the small reward do not show this suppression. Previous studies show that cSNC is a consequence of an aversive emotional state experienced when a negative discrepancy between the expected and the obtained reward occurs. Some researchers call this discrepancy frustration and pose that it is closely related to fear and anxiety. Consistent with this view, the administration of the benzodiazepine chlordiazepoxide reduces the size of cSNC, increased hypothalamic-pituitary-adrenal activation levels happen after animals have exposure to downshifting situations, and lesions in the lateral amygdala attenuate the cSNC while lesions in the corticomedial and central nuclei eliminate it. Most jobs have addressed this phenomenon based on the analysis of mean-level responses of all experimental animals. However, there is a range of individual differences in the animals? responses to a reward devaluation event that suggests that experimental animals do not have a homogenous response; selective breeding studies also support this idea. Here we used a data analytic method for identifying heterogeneous samples to analyze divergent behavior patterns in cSNC in rats. Specifically, we analyzed the data of 53 animals with latent class growth analysis (LCGA). This particular technique is highly relevant for longitudinal data with relatively small samples. We found two profiles: animals showing negative contrast and no recovery, and animals expressing both negative contrast and recovery of consummatory response. Our results are consistent with previous literature who imply that individual differences do exist when animals have exposure to an incentive downshift.