Injormation Storage in Nerve Cells 225 



blank interval which is relevant to the electrical aspects of the 

 memory mechanism discussed earlier. Yet the total recovery pat- 

 tern in retrograde amnesia stresses the lability and vulnerability 

 of the most recently acquired experience and suggests that it 

 is not only the electrical or short-term aspects of memory which 

 consolidate; some form of consolidation must also occur in the 

 structural or "permanent" stage of information storage (12). 



A molecular mechanism for information storage must embrace 

 all these features. As a provisional target we might envision a 

 molecular species which may be altered by ionic flux but once 

 altered is immune to other electrical interventions, which has 

 nothing to do with basic metabolic processes, which can replicate 

 itself within a cell and which can alter the output of that cell so 

 as to disseminate its "spoor" to the next cell along the pathway. 

 But to envision is not to identify. The target promises to be elusive. 

 The analogy of the inirror focus may be rough indeed but it is 

 pertinent to recall that the alterations observed in electrical and 

 chemical properties are brought about through the same neural 

 pathways available to physiological stimulations. No quantitative 

 relationship between these data and the events responsible for 

 behavior is implied. Perhaps there is no relationship at all. Never- 

 theless, used as an experimental tool this model and the observa- 

 tions it has yielded so far indicate that we have in hand, to see 

 and to investigate, clear-cut and permanent changes in cellular 

 and synaptic properties related to the past history of that cell 

 or synapse. 



ACKNOWLEDGMENTS 



These studies were supported by U.S.P.H.S. grant B-3543. I 

 wish to express my gratitude to the many individuals who have 

 helped in various aspects of these investigations. Special appre- 

 ciation is due to Dr. K. L. Clhow and Mr. Paul Naitoh for help 

 in some of the experiments and to Professor Lincoln Moses for the 

 statistical analysis. Gratitude is hardly the word to express the 

 indebtedness to my wife, Dr. Lenore Morrell, whose forebearance 

 with dinners grown cold and evenings in the laboratory made 

 this work possible. 



