EFFECTS ON BIOELECTRIC ACTIVITY OF NERVES 



579 



Si 



1.4 



1.2 



1.0 



08 



4 



2 



00 



Beginning of Beginning of 

 Stimulation X- irradiation 



at 50/sec 



-o Spike Amplitude 



-^ Sensitivity 



-• Conduction Velocity 



20 



20 40 



MINUTES 



60 



80 



Fig. 3. Mean relative responses of 10 caudal nerves stimulated at 50 per sec for 20 

 minutes before and during x-irradiation. The stable values preceding stimulation, shown 

 in Fig. 2, are omitted from this graph. The initial drop in activity represents a fall in 

 response due to stimulation. Dose rate: 6 kr per min. 



velocity. Under x-irradiation, nerves subjected to frequent stimuli failed to 

 respond as long as unstimulated nerves. 



Figure 5 shows the response of a typical nerve which, after a period of 

 stabilization, was irradiated until a definite increase in spike amplitude was 

 observed. The x-ray beam was then turned off, and for 5 hours the response 

 of the nerve was followed, with stimuli onlv at the time a recording was 



