The effect of satiation upon conditioned and unconditioned salivary responses.

There is no doubt that the conditioned food saiivary reflexes are influenced by the intensity of hunger. However, there is no agreement as to whether this influence is direct or mediated by motor behavior. The data are also conflicting concerning the effect of hunger or satiation upon the unconditioned salivary response. Thus, Finch (1938) found that hunger affects the conditioned and unconditioned salivation in the same way; the more satiated the animal the smaller are salivary CRs and URs. Zener and McCurdy (1939) measuring both amount and rate of salivation in addition to the chewing movements established less clear relations. Satiation caused in their dogs a consistent decrease of conditioned sali-vation, but an increase of unconditioned secretion, with concomittant slowing of chewing rate and prolongation of eating time. The rate of salivation decreased markedly in case of CR and only slightly during eating. There was no consistent change of amount of saliva per chew. More recently James et al. (1966) observed a marked drop in salivary CRs within a session and concluded that salivation could be used as a convenient and practical index of drive. Using an improved salivary fistula (Soltysik and Zbrozyna 1957) and voluminographic recording by the use of Kozak's method (Kozak 1950) it is possible to obtain smooth and reliable records of salivary CRs and URs showing immediately the rate of secretion (Fig. 1). In the present report data is shown from an experiment aimed at studying,the effect of gradual satiation during prolonged sessions upon conditioned and un-conditioned salivation. Satiation was produced by prolonging the session (i.e., by increasing the number of trials) until the animals refused to eat. The standard portion of food used as the reinforcing US was about 70 g.