Integrated Somatomotor, Cardiovascular and Gastrointestinal Adjustments Induced from the Cerebellar Fastigial Nucleus



Behavioural, cardiovascular and gastric responses induced by fastigial stimulation wereobserved in conscious cats with gastric fistulas, indwelling fastigial electrodes and arterial catheters. Fastigial stimulation elicited oral behaviours, e.g. grooming and chewing, together with tachycardia and pressor responses, while gastric motility was unaffected in most cases as was gastric hydrochloric secretion. In subsequent experiments on the anesthetized animals it was found that the same fastigial area could suppress the intestino-gastric inhibitory reflex. Fastigial influences on small intestinal motility were investigated in anesthetized cats, well recovered from surgical isolation of intestinal loops whose motility could therefore be recorded without laparotomy. Fastigial stimulation either depressed or did not influence ileal motility before laparotomy but after this procedure excitatory responses were uniformly recorded. This reversal is explained by a fastigial suppression of inhibitory intestinal reflexes, elicited by the laparotomy.