Gustation and ingestive behavior in the rat.

Gustatory deafferentation was produced by combined bilateral section of the chorda tympani and glossopharyngeal nerves and the pharyngeal branch of the vagus nerve. The procedure did not affect the condition of the mouth, impair orientation to sensory stimuli, or severely disrupt the consummatory sequence. Nevertheless, deafferented subjects showed reduced responsiveness to food and water, elevated QHCl aversion thresholds, and impaired feeding efficiency. Food and water intake and body weight remained below control levels for at least 40-50 days postoperatively. Food intake deficits were not observed when the rats were offered ad lib pablum, a result suggesting that increased palatability could compensate for decreased gustatory input. The order of recovery of food intake through different diet types suggests a heightened responsiveness to taste stimuli. The effects of gustatory deafferentation are compared with those seen after section of trigeminal orosensory nerves (Jacquin & Zeigler, 1983), and the differential contributions of oral "taste" and oral "touch" are discussed.