306 BRAIN MECHANISMS AND LEARNING 



Stimulation of the reticular formation elicited the conditioned reflex, a 

 neurotic state was produced by the administration of a painful stimulus 

 simultaneously with the positive sound stimulus. In this state all signs of 

 neurosis (barking, defaecation, urination, escape reaction and fear) were 

 elicited by the sound stimulus. When in this state stimulation was begun 

 the animal calmed down and, as a result of stimulation, the conditioned 

 reaction appeared. However, a few minutes after the cessation of stimula- 

 tion the signs of neurosis were found to be dominant again. It should be 

 mentioned that the conditioned reflex elicited by stimulation of the 

 reticular formation appeared only if the parameters of stimulation ex- 

 ceeded a certain limit. If the intensity of the stimulus was increased 

 emotional reactions (fear, escape reaction), appeared instead of the 

 orientation or conditioned reflexes. 



From the above-described experiments two conclusions may be drawn: 



1. The conditioned reflex elicited by stimulation of the diffuse activa- 

 ting system depends on the environment which influences the animal 

 through the specific projection system; 



2. The neurotic state is due to a break in the temporary connection 

 between the specific and diffuse projection systems. 



From the foregoing it is obvious that, even in the elementary manifesta- 

 tions of behaviour, a whole series of neural and humoral processes are 

 involved. Present-day data do not indicate what neural structures are 

 responsible for the behavioural changes caused by a certain endocrine 

 factor. However, they call attention to the fact that in the development of 

 normal as well as neurotic states, humoral factors play an important role. 

 The individual differences in the endocrine system will probably explain 

 why the establishment and stability of temporary connections elaborated 

 under similar condition as well as neurotic phenomena show those great 

 individual variations. 



GROUP DISCUSSION 



MoRRELL. I wonder if Dr Lissak has considered the role of diurnal variations in 

 hormonal output in evaluating both electrical and behavioural signs of condition- 

 ing. One might expect that hormonal influences on behaviour and on conditioning 

 would vary with the time of day at which the experiments were carried out. This 

 might be another variable to be added to those determining individual differences 

 with which much of Dr Lissak's previous work has been concerned. 



The data on hypophysial adrenocortical influences are most interesting and 

 bring to mind some unpublished observations from our laboratory which indicate 



