Identifying profiles of recovery from reward devaluation in rats

Abstract

In humans and other mammals, the unexpected loss of a resource can lead to emotional conflict. Consummatory successive negative contrast (cSNC) is a laboratory model of reward devaluation meant to capture that conflict. In this paradigm, animals are exposed to a sharp reduction in the sucrose concentration of a solution after several days of access. This downshift in sucrose content leads to behavioral responses such as the suppression of consumption and physiologic responses including elevation of corticosterone levels. However, response heterogeneity in cSNC has yet to be explored and may be relevant for increasing the validity of this model, as humans demonstrate clinically meaningful heterogeneity in response to resource loss. The current analysis applied latent growth mixture modeling to test for and characterize heterogeneity in recovery from cSNC among rats (N = 262). Although most animals exhibited recovery of consummatory behavior after a sharp drop in consumption in the first postshift trial (Recovery class; 83%), two additional classes were identified including animals that did not change their consumption levels after downshift (No Contrast class; 6%), and animals that exhibited an initial response similar to that of the Recovery class did not recover to preshift consumption levels (No Recovery class; 11%). These results indicate heterogeneity in recovery from reward loss among rats, which may increase the translatability of this animal model to understand diverse responses to loss among humans.

Behavioral neuroscience of psychological pain

“…Although this hypothesis has been supported by behavioral, pharmacological, hormonal, and neuroanatomical evidence , only a few studies have systematically explored the genetic basis of individual differences in psychological pain (Torres and Sabariego, 2014). There are well-defined individual differences in recovery from reward devaluation (S. Papini et al, 2014) that respond to selective breeding (Flaherty et al, 1994;Ortega et al, 2014c). But the bulk of information comes from established strains.…”

Hypoalgesia Induced by Reward Devaluation in Rats

“…Thus, there was no evidence that prior downshift or ethanol experience had a measurable effect on the size of the cSNC effects observed in these experiments. There are individual differences in the extent to which rats respond to the downshift event in the cSNC situation [ 27 , 28 ] that are responsible for variability across experiments. What seems clear is that variations in the strength of the cSNC effects reported in these experiments did not prevent hypoalgesia from developing.…”

When loss hurts: Psychobiological basis of frustration

“…Otros estudios han puesto de manifiesto la existencia de diferencias individuales en la sensibilidad al dolor físico y psicológico, así como en la respuesta a su manipulación farmacológica. El análisis de una muestra extensa indica que, aunque la mayoría de los animales se recuperan rápidamente de una devaluación del 324% de sacarosa, el 11% no muestra signos de recuperación (Papini et al, 2014). Esta diferenciación de perfiles de recuperación se utilizó también en un estudio de selección artificial.…”