68 



RAGNAR GRANIT 



n 1 1 r 



J I 1 1 L 



I I I L- 



I /I I U 



Fig. 3. A-G are curves plotted from experiments in which range of Fn was large. 

 The straight lines have been drawn to reproduce formula F,, = aFi + b. The 

 constants«and6arefrom A toG: 1-25, 10; 0-97, 2-4; 108, 10; 0-84, 8-9; 

 1-17, -0-6; 0-92, 3-7; 0-84, 8-8. Curve H is the average from thirty-three 

 experiments, a = 1-04; 6 = 2-6 imp/sec (Granit et al., 1960). 



rate of discharge could be inhibited by reticular stimulation. 1 mention this 

 chiefly to show that our method is convenient for studies of this type and to 

 underhne that some of the discrepancies in work with Renshaw cells may 

 well have been due to influences of this kind. Considering how little we 

 know about supraspinal mechanisms of control, even for cells which have 

 been studied extensively, much experimentation will be required before we 

 know when and how in complex events Renshaw cells are excited or sup- 

 pressed. For the time being it would be wrong to look upon them merely as 

 automatic at the spinal level. We know that in truly tonic cells, such as those 

 of soleus, recurrent inhibition is particularly strong (paper no. 1 ; Kuno, 

 1959; Eccles et al., 1960) and in those cells it is likely to work in close co- 

 operation with their long-lasting after-hyperpolarization. found by Eccles 

 et al (1958). 



