Effects of isolation in adulthood on frustration and anxiety

In consummatory successive negative contrast (cSNC), when rats receive 32% of sweetened water and are unexpectedly exposed to 4% of the same solution, they consume less than those who received 4% regularly. In consummatory extinction (cE), rats receiving a 32% or 4% sugar solution stop lapping when presented with an empty tube. In both cases, these situations trigger an aversive emotional reaction similar to fear and anxiety called frustration or negative contrast effect. Isolation conditions in adulthood increase anxiety responses. We describe an experiment in which isolated or grouped rats in adulthood are evaluated in an elevated plus maze (EPM), in cSNC and cE. Results show that rats in groups express less anxiety and activity in EPM and more persistence in cE than isolated rats. There are no differences between the two housing conditions in cSNC. We discuss these results on the basis of frustration theories.

► Consummatory successive negative contrast (cSNC) and consummatory extinction (cE) are experimental procedures to evaluate frustration in rats.
► Isolation treatment produces anxiety-like behavior in rats.
► We examined this treatment in the animal response to frustration.
► Isolated animals were more anxious in elevated plus maze and cE but did not differ with controls in cSNC.