SOME THALAMIC AND CORTICAL MECHANISMS OF TASTE 



319 



animals, two descending runs each. The lowest concentration marked by 

 the large dots was below threshold, the second was 10 X stronger and the 

 third 10 X stronger than the second, placing it in each case well into the 

 range of maximum preference or aversion. I should mention that the 

 squirrel monkey does show a preference for NaCl on an ascending series, 

 but these data are not complete as yet. 



It was very difficult to maintain isolation of these extremely small and 

 densely packed cells for very long periods. Therefore, each stimulus 

 application was limited to about three seconds, but all solutions were 

 presented a sufficient number of times to be certain of the result. 



Figure 9 shows the response profiles for 27 units. Each profile shows 



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I- 

 < 



.J 



UJ 





100 = 1 M NACL 

 0.1 M MCL 

 01 M OTHCL 

 ION sue. 



L 



7 



Li 



k 



F 





\L Li 



ELI 





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Fig. 9. Response profiles for twenty-seven thalamic neurons isolated in the 

 ventromedial nuclear complex of the squirrel monkey. 



whether or not the unit was activated by a particular substance at a par- 

 ticular concentration, but does not indicate the magnitude of the response. 

 A number specifies how many units had the same response profile. In the 

 column at the extreme left are profiles for eight units which were responsive 



