Differential arousal response to gustatory stimuli in the awake rabbit

ECoG arousal response as elicited by deionized water and by several concentrations of sweet, salty, sour and bitter tasting substances, all applied intraorally, were studied in the awake restrained rabbit. The study was carried out on 17 chronic preparations of adult male animals (2.6 kg average body weight). Water as a stimulant was presented in 60 trials and tastants across qualities and concentrations in 245 trials. Arousal was quantitatively characterized by its duration, frequency increment and amplitude decrement as compared to prestimulus conditions. Arousal induced by tastants was compared to that induced by water. Water and tastants induced arousals differentiable by the parameters measured. Further, most tastants produced a dose-dependent response. Comparison of ECoG and behavioral data clearly indicate that tastants inducing behavioral aversion also produce an arousal which significantly differs from response to water while behavioral preference was found not to show similar correspondence with ECoG data. The possibility of using arousal as an objective indicator for taste aversion is discussed.