278 



BRAIN MECHANISMS AND LEARNING 



associated with EEG 'arousal' (Gauthier, Parma and Zanchctti, 1956): 

 therefore, T eil^ect was compared with changes resulting from application 

 of certain EEG 'activating' agents, (i) MRF stimulation (contralateral to 

 SS) reduced amplitude and duration of N3, P3. N2, and, to a lesser extent, 



T EFFECT 



I. FREE MOV. 



II. FLAXEDIL 



«//. 



*t^^^ 



t t 



/. FREE MOV. 



CSC ^^f^^(,/A''"^"""' 



,\ VWV*"*^ /\a/ 



//, FLAXEDIL 



Fu.. 'J 



PERSISTENCE OF TONE EFFECTS IN FLAXEDILIZED PKEPAKATION. I, T cftccts ill freely 



moving, unanaesthetized cat; II, same cat under Flaxedil: electrographic 

 effects were comparable. 



Ni ; intensity of effects could be graded by variations in central excitation 

 voltages: as far as morphological mutations are concerned, MRF excita- 

 tion and T effects were indeed comparable (Fig. 10). (li) Tones that after 

 training provoked results described above had induced similar (diough 

 usually less noticeable) effects when novel (on fu'st application) (Figs. 5 — 



