752 GENERAL DISCUSSION 



the fluorescent effect in the brain stem, the lower brain stem, hippocampus or 

 parts of the limbic system, one might wonder whether certain things might not 

 be happening here. Our receptor system and peripheral nerves, perhaps at some 

 level of radiation, sensitize temporarily to give some of these results. Where the 

 brain itself is radiated or perhaps the whole body, the influence of this might sug- 

 gest that the reticular activating system and the associated limbic system might be 

 somehow sensitized. This may not be as absurd as it first sounds, because in Dr. 

 Arnold's results a number of his tests were essentially negative; but emotionality 

 was one of the things in the open field tests which was not measured. In 

 another paper by Davis, he pointed out particularly negative results on some tests 

 but noted that non-visual survey and restlessness might be coupled with a slight 

 sensitization to the reticular activating mechanism to incoming sensory modes. 

 I wonder whether others, Dr. Monnier particularly, since he has been concerned 

 not only with reticular activating systems, but also with the diffuse thalamic 

 nuclei, would see in this a possibility. Certainly, as Dr. Furchtgott mentioned, the 

 sensory or perceptual modalities may be sensitized or desensitized, and this may 

 be a determining factor in learning tests or discrimination tests. So we have to 

 look carefully at the kind of measurements and observations we are making and 

 attempt to determine what particular system or element in the system may be 

 responsible for some of the results. 



Roger T. Davis (State University of South Dakota, Vermillion, South Dakota): 

 Dr. Lindsley, I should like to say that in looking at some of the things which have 

 been reported in the literature, we find lower distractability, changes in posture, 

 narrowing of attention, relative decrease in initiation of aggression and manipu- 

 lation of inanimate objects. These things suggested to me what you have said, but 

 I did not feel I was enough of an anatomist to make that statement. I am glad 

 you did. 



Donald B. Lindsley: I do not think I am enough of an anatomist to make it, 

 either, but I have been at least concerned with it. I would like to make a final 

 statement, since this is the last session of our meeting. I think we are all agreed 

 that this has been a fine meeting, and I think we would also like to extend our 

 thanks to our two hard-working co-chairmen. Dr. Tom Haley and Dr. Ray Snider, 

 to the Public Health Service, and the Atomic Energy Commission for having 

 made this conference possible. We can all now not take AET or TEA, but TWA. 

 The meeting is adjourned. 



