GENERATION AND TRANSMISSION OF SIGNALS 41 



(Arduini et al, 1957). The induced waves are blocked by antidromic 

 stimulation of the secondary olfactory pathways and are therefore most 

 likely to be attributed to activity in secondary neurons. There is a close 

 resemblance between the potential developed in the olfactory membrane 



Fig. 6. Simultaneous recordings of the electro-olfactogram and the bulb 

 response. Vertical bars 1 mV. Time mark 1 sec. (From Ottoson, 1959b.) 



and the slow response of the bulb (Fig. 6). This is of particular interest as 

 the bulb response may be regarded as of the generator type. As such it 

 forms the link between the incoming signals and the impulse message 

 carried to the olfactory cortex. Information about the functional pro- 

 perties of the bulb has also been obtained in studies of the response pro- 

 duced by electrical stimulation of the olfactory nerve fibres. The response 

 developed by the bulb at the arrival of a synchronous volley of afferent 

 impulses consists of a negative potential with a duration of about 150 msec. 

 This response (Fig. 7) is composed of two separate components which may 



Fig. 7. Response of the olfactory bulb to repetitive electrical stimulation (1 sec) 

 of the olfactory mucosa. Vertical line 1 mV. Time mark 100 msec. (From 



Ottoson, 1959c.) 



