The Effects of a Context Switch following Serial and Simultaneous Feature-Negative Discriminations

Results suggest that the serially trained feature acquired the properties of a negative occasion setter, and responding to the target was more difficult to inhibit when it was tested in a different context.

Abstract

Two experiments with rats examined the effects of a context switch on inhibition that was acquired following either simultaneous or serial feature-negative (FN) discriminations. A "target" stimulus was paired with food when presented alone, but not when compounded with, or preceded by, a second "feature" stimulus. A change of context following training did not disrupt inhibition conditioned to the feature. Nonetheless, responding to the target was more difficult to inhibit when it was tested in a different context. The observed loss of suppression was especially evident when the target had been trained in a serial FN discrimination. Results also suggest that the serially trained feature acquired the properties of a negative occasion setter. In a simultaneous FN discrimination, the feature may inhibit responding to the target by directly suppressing the representation of food and by activating the target's own context-specific inhibitory association with food. In a serial FN discrimination, the occasion-setting feature may inhibit responding to the target primarily through the latter mechanism.