Impairment of salivary reflexes after lateral hypothalamic lesions in dogs

The effects of lateral hypothalamic lesions on salivary conditioned and unconditioned reflexes were investigated on seven dogs. Subsequent to the operation during the period of aphagia and hypophagia a total lack (6 dogs), or a decrease (1 dog) of conditioned salivary reaction was found. Strong diminution of unconditioned reactions and intertrial salivation were observed. At the end of the observation period (7 months) the conditioned and unconditioned salivary reflexes were still diminished reaching levels of 12-54 percent and 35-75 percent respectively in comparison with the pre-operative period. The mechanism of the impairment of salivary reactions was discussed.