ELECTRICAL ACTIVITY IN THE OLFACTORY SYSTEM 



79 



fibers, and they summated poorly : however, from some sites effective 

 integrator records were obtained although they were generally less promi- 

 nent than the responses on the side of the lesion. In such a preparation, 

 repeated presentation of the same odorant failed to produce any diminution 

 (i.e. habituation) of response. Furthermore, as Fig. 9 shows, the responses 

 tend to rise with increasing concentrations of amyl acetate. This effect 



n-AMYL ACETATE 



LBI 



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RB 



B2 



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-269 -2-61 

 Imin 



RB3 



PN 



-4-39 -361 -331 -319 -2-99 -2-91 -2-79 



LOG MOLAR CONCENTRATION 



Fig. 9. Summated responses to an amyl acetate concentration series. Spike dis- 

 charges from bulbar sites are compared with activity recorded simultaneously 

 from electrodes implanted in the cribriform plate region (P.N.). The recorder 

 was turned off for a minimum of 5 min between successive presentations of a 



stimulus. 



is seen more clearly in Fig. 10, where stimulus-response curves derived 

 from 7 bulbar sites and one peripheral site are compared. With one 

 exception the curves of lowest amplitude were derived from bulbar points 

 on the side opposite the lesion. The peripheral curve (P.N.), and several 

 bulbar curves show little tendency to flatten at the highest concentrations 



