[Formation of conditioned reflexes to number of sequential stimuli in the dog]

The present experimental study deals with question, whether dogs are able to orient their behaviour to stimuli which differ only by the number of identical clicks presented in successive series with variable interstimulus interval. Some dogs elaborated alimentary or defensive motor conditioned reflexes nd differentiations to them being in classical conditions in experimental chamber. In other dogs running to the feeding trough was elaborated and a differentiation to it in response to series of clicks differing only by one signal. It was established that the parameters of conditioned positive and negative reactions (latency, rate and realization frequency) statistically depended on the number of clicks in the series and did not depend upon its temporal characteristics (interstimulus intervals and duration). The conclusion is made that in CNS of dogs, elementary form of counting a signals takes place, and that the integrated result of this count might serve as a key to evoke positive or negative conditioned reaction.