TASTE STIMULATION AND PREFERENCE 

 BEHAVIOR* 



C. Pfaffmann 



Brown University 



One intriguing aspect of the chemical senses is the potent control of be- 

 havior which they effect in invertebrates and vertebrates, including mam- 

 mahan forms. The almost ubiquitous " sweet tooth ", the preference for 

 sugars in many but not all species, and the compensatory taste cravings 

 which appear in states of physiological need or endocrine imbalance are 

 well known, the latter particularly from the work of Richter (1942) and 

 subsequent workers. A number of investigators have examined both 

 taste sensitivity and taste preference in an effort to determine the relative 

 roles of the gustatory stimulus itself, post-ingestional factors, and learning 

 effects. Tn our work, we have looked particularly at certain features of 

 the afferent input and its central neural mechanism in relation to behavior, 

 the so-called preference and aversion responses for different taste stimuli 

 displayed by the laboratory mammal, primarily the rat. 



Especially dramatic is the enhanced intake and preference for NaCl 

 following induction of physiological need by adrenalectomy, dietary reduc- 

 tion of NaCl, or other physiological manipulation. And, ahhough there 

 has been much work on the subject, there is still debate as to the precise 

 mechanism by which the specific hunger for sodium chloride is mediated. 

 Several noteworthy points may be mentioned. 



1. The normal rat, apparently well supplied with NaCl, displays a pre- 

 ference for hypotonic and isotonic solutions and an aversion to hyper- 

 tonic salt solutions. 



2. Adrenalectomized or deprived rats show an enhanced intake or pre- 

 ference at all concentrations with the result that the preference threshold is 

 lowered, i.e. animals show a preference for weak solutions at a concentra- 

 tion below those taken by normal animals and they take more of the stronger 

 suprathreshold solutions. 



3. The preference for sodium salts in the sodium deprived animal is 



highly specific ; NaCl is taken in preference to KCl, NH4CI, CaClg, or 



other taste stimuli. 



♦Presented at the First International Symposium on Olfaction and Taste Wenner-Gren 

 Center, Stockholm, September 2-5, 1962. Supported in part by a grant from the 

 National Science Foundation. 



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