| Abstract: | Spike response to unconditioned electrocutaneous stimulation was investigated in cortical neurons of areas 3 and 4 in untrained hungry cats during heightened excitation motivated by food presentation and when at rest. This reinforcement led to changed background activity level, reduced intensity of the initial stages of spike response, and disappearance of late neuronal response. Neuronal response of the same cortical area to a conditioned stimulus (a clicking sound) during reduced food motivation (the animals being sated during the course of the experiment) was also studied under the effects of instrumental feeding reflex. Coordination between the timing of neuronal response and their corresponding movements was discovered from comparing response pattern accompanying the execution of paw-placing (conditioned reflex and intersignal) movements and those recorded at different levels of food-induced excitation, as well as a similarity between these reactions. It was found that the initial stages of neuronal response to a conditioned signal only occurred during contraction of the brachial biceps muscle, while coordination between their timing and that of EMG changes was dependent on the animal's degree of satiation. Findings indicate the possibility of food-induced excitation substantially influencing spike response pattern in somatic cortex neurons.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 19, No. 6, pp. 725–735, November–December, 1987. |
