SENSORY NEURAL PATTERNS AND GUSTATION 213 



degree of avoidance of all three. In both tests, the following concentra- 

 tions were used in a random fashion to insure that the discriminations 

 were not developed on the basis of intensity differences : KCl and NH4CI — 

 0.01, 0.03, and 0.1 m; NaCl— 0.003, 0.01, 0.03 and 0.1 m. The results are 

 similar to those obtained in the first behavioral test. Depression of drinking 

 generalized between KCl and NH4CI, but not so much between either of 

 these and NaCl. 



To summarize the results of the behavioral tests, responses learned to 

 KCl generalized to NH4CI and vice versa. Responses learned to either 

 KCl or NH4CI generalized much less to NaCl and vice versa. It appears 

 that, for the rat, KCl and NH4CI taste more nearly alike than either do 

 to NaCl. Therefore, in addition to concluding that there are many fiber 

 types in gustation, one may conclude that the neural message for gustatory 

 quality is a pattern made up of the amount of neural activity across many 

 neural elements. 



These data support an across-fiber pattern theory for taste quality 

 sensitivity. These patterns which signal the quality of the taste stimulus 

 are developed across a great number of fibers. The various fibers involved 

 show considerable diversity in their sensitivity to taste stimulation ; this 

 diversity in sensitivity prevents easy fiber classification, but provides the 

 basis for the across-fiber patterns. 



ACKNOWLEDGEMENTS 



The able technical assistance of David A. Marshall and John A. Pooler, 

 and the advice of C. Alan Boncau and Irving I. Diamond were very much 

 appreciated. 



REFERENCE 



Pfaffmann, C. 1955. Gustatory nerve impulses in rat, cat and rabbit. /. Neuropliysiol. 

 18, 429-440. 



