R. W. GERARD 33 



weeks 111 the laboratory rat. The effect disappears in 5 or 6 weeks. The effect is not 

 found with other anaesthesia. 



Gerard. I am not prepared to go along with the extreme psychiatrists who say 

 that learning is all over the body and not in the brain, nor with the slogan that 

 'we think with our blood'. We think in the nervous system and in the upper part 

 of it, but there is continuity. The same kind of mechanisms, which are specialized 

 in the nervous system as a basis tor recording experience, probably evolved from 

 basic cellular processes, which are seen at the chemical level, hi the case of the 

 flatworm this is closer to the level ot total behaviour. As to the second point, the 

 action of these drugs on the fixation process and on learning processes is very 

 complicated and depends on many parameters. With increasing doses of mepro- 

 bamate, one finds an increasing interference with the learning curve. These experi- 

 ments were on rats with an avoidance conditioning, given massed trials and tested 

 the next day. The drug, when given, was injected i hour for meprobamatc, or 

 3 hours for the barbital (depending on maximum time of action), before the learn- 

 ing experience. Rats were given electroconvulsive shocks at i, 2, 5, or 15 minutes 

 after the mass runs, which were completed usually well within 15 minutes total 

 time. Although meprobamate definitely interfered with learning, it did not inter- 

 fere with the hxation; it even improved it. hi other words, an electric shock at one 

 minute did not interfere so much with retention on second test of a rat with, as 

 for one without, meprobamate. We are checking to be certain that a raised threshold 

 is not a fictor, even though all shocks gave typical convulsions. The phenobarbital 

 had a marked effect in prolonging fixation time; as shown by much deterioration 

 with electroshock, and the greatest deterioration with the closest shock. It did not 

 interfere with initial learning. Your findings seem contrary to what happened in 

 our laboratory; we should examine differences in conditions. 



Chow. May I just make a point about this ffatworm work, because that work 

 seems to me to be most striking. If it is true it will probably inffuence our thinking 

 about learning at the cellular level. There are two points I wish to make about this 

 particular piece of work, the results of which I think should be accepted with some 

 caution. First, there are probably nerve cells in the nerve tract, therefore you have 

 a second or caudal half which still remembers the problem, which may not be due 

 to memory in the nerve fibre itself. Secondly, a very important point is that 

 apparently an essential control was not made. This control is : they should have a 

 group of animals which are given a series of shocks without learning, and cut them 

 into two, wait until they regenerate and do the conditioning, and see if this group 

 without previous training, also show a fast learning. 



Gerard. These controls have now been done. I talked to McConnell some 

 months ago and, as I recall, results were going in the proper direction. Even with- 

 out them, however, it seems hard to explain awa\' the fict that, even if there are a 

 few neurones in the tail as compared to the many in the head, the tail did do as well 

 as, or better than, the head. Maybe if one gets too much stuff"in the head, ideas get 

 fixed in a certain way and performances are no longer malleable; a sort of ageing 

 phenomenon. The work will certainly have to be examined carefully, because it is 

 a very disturbing finding. However, the appearance of certain phenomena at this 

 primitive level does not necessarily explain those at a more complicated level. It 

 may well be true that this is a perfectly good type of learning, but it is certainly not 

 the whole story of our learning. Let me give one example of this: Many years ago 



