Electrophysiological Analysis of Conditioned Reflexes where the Conditional Stimulus is the Stimulation of Phylogenetically Different Parts of the Cerebellum

Abstract

The production of a food-procuring conditioned reflex to the stimulation of phylogenetically different nuclei of the cerebellum was shown in cats. A correlation was shown between the electrophysiological and behavioral indices of food-procuring conditioned reflexes. Changes in the recruiting-like potentials recorded from the cerebral cortex were found to the low-frequency stimulation of the nuclei dentatus and interpositus, the stimulation being used as a positive conditional stimulus. It was shown that the phylogenetically different nuclei of the cerebellum are functionally heterogeneous. The development of conditioning and conditioned inhibition, produced to different parameters of stimulation to the cerebellar nuclei, showed mainly the inhibitory possibilities of the cerebellar projections to the forebrain through the nonspecific thalamic structures as well as the activating nature of the cerebellar influences through the reticular formation of the midbrain.

Behavioral detection of subcortical stimuli: Comparison of somatosensory and "motor" circuits.

“…Stimulation of these structures seemed to be of additional interest in view of conflicting evidence that stimulation of the cerebellum, at intensities below those capable of inducing involuntary movements, is neither accompanied by overt sensory experiences in humans (Nashold & Slaughter, 1969;Snider & Wetzel, 1965) nor able to support conditioned behavior in animals (Donhoffer, 1966). A few studies have found, however, that cerebellar stimulation can act as a conditioned stimulus with intensities well below movement threshold (Asdourian & Andrezik, 1971;Asdourian & Preston, 1971;Fanardjian & Papoyan, 1974). The results of this study confirm and extend the latter observations.…”

“…We did not obtain sufficient data on stimulation of the fastigial nucleus to allow any statement concerning the efficacy of its stimulation for detection. The stimulus intensities used in this study did not produce any signs of arrest reactions, emotional changes, or various consummatory behaviors that can occur as a corollary of cerebellar or VL stimulation (Buchwald & Hull, 1967;Fanardjian & Papoyan, 1974;Hunter & Jasper, 1949;Manzoni, Sapienza, & Urbano, 1967;Reis, Nobutaka, & Nathan, 1973).…”

“…This does not adequately explain our findings or those of (Asdourian & Andrezik, 1971), who found that rats continued to utilize stimulation of cerebellar cortex as a signal to escape shock, even when stimulus intensities were as low as 10%-20% of those that produced overt movements. Fanardjian and Papoyan (1974) found that stimulation of the deep cerebellar nuclei in the cat could act as a conditional stimulus with intensities 62%-67% of those that caused involuntary movements.…”