228 BRAIN MECHANISMS AND LEARNING 



GROUP DISCUSSION 



Olds. I would like to address myseli to the remarks on the reticular tormatioii 

 and its differentiation. We also found differentiation in the reticular formation 

 based on the dichotomy between the aversive and approach behaviour. We find 

 that stimulation in the dorsal medial tegmentum produces escape. Stimulation in 

 the ventral lateral tegmentum produces approach of the self-stimulation variety — 

 in between there are overlaps. 



First — the type of electrical activity which Dr Anokhin showed as typical of 

 aversive stimulation did not appear in the ventral lateral placements but did appear 

 in dorsal medial placements. The type of electrical activity which he showed as 

 characteristic of alimentary stimulation did appear in the ventral lateral place- 

 ments, but not in the dorsal-medial placements. Mv question is whether the 

 electrodes used by Professor Anokhin were in the same parts of the reticular 

 formation or in different parts. 



My second question is: We have applied chlorpromazine and we have obtained 

 results which are superficially in conflict with Dr Anokhin's results and we have 

 checked our data. This is it: Chlorpromazine inhibits the self-stimulation response 

 rotally in the rat at 2 mg. per kilogramme — a dose which has very little effect on 

 the escape reaction produced by stimulation of the dorso-medial tegmentum. 

 This is different from Neprobamate and Nembutal which inhibit the escape reaction 

 and have little efiect on the self-stimulation response. 



Anokhin. I suppose that the difference here is to be found in the specific localiza- 

 tion of the stimulation. A given reaction may be induced from difl:erent points of 

 the functional system ; it can be provoked by natural stimuli, as by electrical ones. 

 Yet, if electric stimulation is applied to' a given spot of the reticular formation 

 which is on the excitation pathway, after synapses which have been made sensitive 

 to chlorpromazine, it may happen that the drug will have no blocking effect on the 

 animal's defence reaction, wluch had been induced by direct excitation. 



Grastyan. I am in perfect agreement with Professor Anokhin about the concep- 

 tion of the functional specificity of reticular activating influences. I think we 

 also obtained in our own experiments evidence confirming this supposition : we 

 found that the stimulation of different points in the reticular formation in the 

 hypothalamus had always a specific influence in the sense that it activated only 

 certain behavioural acts, but inhibited others, antagonistic to those of the activated 

 ones. The only point with which I do not agree is the interpretation of the electrical 

 activity recorded in the reticular formation. I cannot believe that it represents a 

 specific activity of the reticular formation (I refer to the 4-6 cycles per second 

 activity see slides 6 (?;/(/ 7). It must be recorded very close to the substantia grisea 

 centralis in the mesencephalon and in my opinion it reflects a special projected 

 activity of the rhinencephalon to the brain stem (hippocampus, entorhinal cortex). 

 It was shown by Dr Adey that abundant connections exist between these two areas. 

 Moreover I have seen this activity to appear in the same point of the reticular 

 formation in both alimentary and defensive conditioned reflexes; thus in my 

 opinion it could not be regarded as representative of a specific function of this 

 reticular subcentre. 



Anokhin. I can give Dr Grastyan the following answer: Comparison of the 

 slow rhythms of the reticular formations of the hippocampus and of the different 



