244 Information Storage and Neural Control 



that evidence and to supplement it with a number of recent findings 

 in our laboratories which will also serve to illustrate some technical 

 innovations we were utilizing for these purposes. 



Before I undertake this task, I wish to emphasize that the hy- 

 pothesis stated does not imply the mediation of memory by 

 regenerative electrical activity. The large literature on the con- 

 solidation process reviewed recently (4) shows that there are at 

 least two phases of memory storage: 1) An early, labile consolida- 

 tion phase, in which the representation of a recent experience is 

 susceptible to severe interference or destruction by numerous 

 chemical or electrical perturbations, and during which memory 

 may well consist of persisting electrical patterns of a reverberatory 

 sort; and, 2) a later stable phase in which such perturbations have 

 no effect, and during which memory is stored in some other fashion, 

 perhaps as a structural modification. This necessitates a coupling 

 mechanism whereby the reverberatory electrical activity main- 

 tained during the consolidation phase gradually stipulates the 

 structural change which will serve to represent it. A number of 

 workers have discussed the possibility that such structural changes 

 might be the specification of macromolecular configurations 

 (5, 6, 25); and, as Dr. Morrell has told you, a number of labora- 

 tories, including his and mine, have presented data suggesting that 

 ribonucleic acid (RNA) may play a role in this function (1, 2, 3, 

 11, 18). Whether or not RNA does participate in long-terin 

 memory storage, it seems reasonable at present to assume that 

 some form of long-term structurally mediated storage does exist. 

 Various data seem to require, further, that the postulated coupling 

 between electrical patterns and the long-term storage device be 

 reversible — that the pattern of iterated or sustained electrical 

 activity stipulate some representational structural modification, 

 and that this structural modification be able to generate an elec- 

 trical pattern identical to the one which established it. 



Time does not permit detailed review here of the evidence which 

 I believe is relevant to the dynamics by which such a representa- 

 tional system is built, but such a detailed discussion has been pre- 

 sented elsewhere (7). For our present purposes, I hope it will suflSce 

 to summarize what I consider to be the salient characteristics of 

 these representational systems: 1) The repeated occurrence of as- 



