Does the interval of delay of conditioned responses possess inhibitory properties?

Abstract

During an experimental session of one hour a conditioned lid response was first established to a tactual-vibratory stimulus followed by a puff of air to the cornea. In a second two and one-half hour session, a delayed conditioned galvanic skin response was set up to a light reinforced after a 20-second interval by an electric shock. On certain trials the stimuli for the lid response were presented within the interval of delay. The amount of change in amplitude and latency of the lid response on these test trials as compared with the magnitude of the same response under normal conditions constituted a measure of the inhibitory characteristics of the interval of delay. Results from 20 subjects showed that the visual stimulus alone produced a mean decrement of 13% in amplitude and a mean increment of 13% in the latency of the test conditioned lid response before any reinforcement of the light by the shock. After a delayed CR had been established, the conditioned lid reaction suffered a decrement of 19% in amplitude when it occurred in the interval of delay. There was a corresponding increment of 15% in latency. Additional control experiments showed that the inhibition of the lid response was definitely a result of the associated order of visual and shock stimuli. (PsycINFO Database Record (c) 2006 APA, all rights reserved)