618 



MARCEL MONNIER AND P. KRUPP 



Threshold Voriation 



VOLT Stimulation of hippocampus 3/sec. 



0.5 - 

 + 0.25 - 





 - 0.?5- 



•900r 



■•AOOr 

 600r 



6 hours 



1 2 3 A 



t Irradiation 

 Cobalt 60 

 Fig. 10. Action of various gamma irradiations on the threshold variations of po- 

 tentials evoked in the cortex by stimulation of the dorsal hippocampus. 



600 r 



900r 

 AOOr 



I 



6 hours 



Fig. 1 1 . Action of gamma irradiations on the threshold variations of potentials 

 evoked in the somesthetic cortex (3 cps) by stimulation of the ventrolateral thalamus 

 (specific thalamocortical projection). 



0.5 - 



+ 0.25- 





 - 0.25 



0.5 



Stimulation of thalamus med. 3/sec. 



eoor 



•900r 



-I 1 1 n 



1 2 3 A 



6 hours 



Fig. 12. Action of gamma irradiation on the threshold variations of the recruiting 

 responses evoked in cortex by 3 cps stimulation of the medial thalamus (unspecific 

 thalamocortical projection). 



