Slow Potentials in the Rhinal Region of the Cat Brain Cortex Related to Visual Recognition Memory

We examined correlation between the development of slow potentials in the rhinal cortical region of cats and results of behavioral testing of visual recognition memory of these animals in the “delayed nonmatching-to-sample” (DNMS) selection version. Among different types of cognitive memory, the recognition memory occupies a special position because the process of taking off (retrieval) of a memory trace from the “stores” can be completely and effectively controlled by the experimenter (this process is initiated only after repetitive presentation of a stimulus identical to that whose trace should be subjected to retrieval or after presentation of an absolutely new stimulus whose trace had not been formed earlier). Recording of the field potentials was performed from the surface of the rhinal cortex using stereotaxically implanted mono- or bipolar Ag-AgCl electrodes after the experimental animals reached a sufficiently high level of successful performance of the test for recognition memory. Analysis of relations between negative slow potentials in the rhinal cortex and the correctness of performance (according to Spearman's nonparametric test) demonstrated the existence of significant correlation between the electrophysiological and behavioral indices of visual recognition memory only within a late portion (final 10 sec but not initial 10 ones) of the retention interval for memorizing the trace of single presentation of a visual stimulus. The data obtained are interpreted as a confirmation of the existence of correlation between generation of negative slow potentials in the rhinal cortical region and the process of retrieval of the sample from the visual memory stores.