J. C. ECCLES 



339 



N 



9 



13 



21 



29 



45 



1 10 



1'4 5 



Mice. 



A. Monosynaptic reflex discharges evoked by stimulating the appropriate dorsal 

 roots and recorded in gastrocnemius nerves 40 days after extraganglionic 

 operative section otthe dorsal roots stimulated in the O records. The topmost 

 record (C) of O and N series is the reflex response before any tetanic con- 

 ditioning. The remaining series show potentiated responses after a conditioning 

 tetanus of 6000 volleys at 400 a second. The figures above each response show 

 the time, in minutes and seconds, at which it was elicited after cessation of 

 the conditioning tetanus, .^nlpliflcation same for O (operated) and N (normal) 

 responses. 



B. The crosses plot the N observations of Fig. lA and the open circles the 

 O observations partly shown in Fig. lA. The vertical line marks the end of 

 the conditioning tetanus, points plotted to left being preliminary controls (c of 

 Fig. I A). Horizontal broken lines give respective mean control heights of reflex 

 spikes. The filled circles are also O responses some 2 hours later than the open 

 circles. Note that initial control level is same as level of residual potentiation 

 surviving at end of first potentiation (open circles to right). Abscissae, time 

 after end of conditioning tetanus (Eccles and Mclntyrc (1953) with permission 

 of thejDi/rH(7/ of Physiology). 



