Effect of the orbital cortex on the neuronal activity of the tegmentum of the midbrain during a feeding reflex in cats.

Chronic experiments on five cats using a model of a conditioned feeding movement reflex were used to study the effect of functional exclusion of the orbital cortex (by anodic polarization with a constant current) on the nature of rearrangements in spike activity in the ventral part of the tegmentum of the midbrain, as well as on the movement component of a conditioned feeding response. Changes in the frequency characteristics, their latent periods, and histogram analyses of spike impulse structure, as compared with increases in the latent period of the conditioned movement response, its duration, and phasicity, demonstrated that the orbital cortex had an activating effect on the responses of ventrotegmental neurons, which correlate with changes in the conditioned movement in this type of feeding behavior. Changes in the conditioned cellular responses were statistically significant only during the start signal (a tone of 600 Hz) before the start of the electromyographic component of the response, i.e., during the preparation and launching period of the movement response.