,' '<..,..' •♦MM) 



Fig. 7 (A) 

 ////////// To d.c. amplifier 



To magnetic relay 

 and photocell 



Fig. 7 (B) 



Fig. 7. (A) Extracellular records of electrical activity in a single stretch- 

 sensitive neuron of the frog. Nerve impulses arise from a maintained 

 depolarization, the receptor potential. Larger degrees of stretch evoke 

 receptor potentials of higher amplitude, which, in turn, generate impulse 

 trains of increased frequency. 



(B) Diagram of the recording situation. M receptor muscle; 

 JV» single remaining afferent fiber, ^i, E^ indifferent and active recording 

 leads, respectively. (From Katz,^® Fig. 6C.) yj-^ji 'j{| , 



24 



