224 Information Storage and Neural Control 



or synaptic activation which established the original alteration. 

 Such "recognition" may be similar in mechanism (still known) 

 to those occurring in morphogenesis and in antigen-antibody 

 reactions. However, it is well to be aware that when we substitute 

 electric currents (whether or not generated by chemical trans- 

 mitters) for the "antigen" we enter a realm of biological phe- 

 nomena not based upon the classical chemistry of atoms and 

 molecules — one in which electron or charge transfer reactions 

 afford the more crucial energizing mechanisms. It is also apparent 

 that those who would consider a role for the nucleic acids in the 

 molecular basis of memory must also explain how an electrical 

 current could induce a molecular rearrangement which is there- 

 after irreversible and immune to further perturbations of its 

 electrical surround. Perhaps the binding of an appropriately 

 modified RNA protein complex to phospholipid would not only 

 protect it from further electrical influence but also fix it to the 

 cell membrane where the function of "recognition" is most likely 

 to take place. 



Finally I should like to return to the beginning and add one 

 more note of complexity to an already complex story. We have 

 mentioned the retrograde amnesia produced by a cerebral con- 

 cussion. Clinical experience gives clear evidence that immediately 

 following an injury the memory loss may extend backwards in 

 time for weeks, months, or even years, so that the patient reports 

 his age as several years younger than is actually the case. During 

 recovery the memory gap decreases gradually with recall of more 

 distant events first and recent events last. Russell and Nathan, 

 in an extensive review (50), have emphasized that the pattern of 

 recovery shows no relationship to the importance of the events 

 remembered. Thus one patient remained amnesic for his marriage, 

 which had occurred three weeks prior to the injury, but recalled 

 perfectly reading a trivial newspaper story six weeks earlier. It is 

 clear that memory returns not in order of importance but only 

 in order of time. To be sure, even under the best of circumstances 

 recovery is never complete; it is almost always possible to demon- 

 strate a complete and permanent loss of memory for the events 

 immediately preceding an injury. Perhaps it is this last, brief, 



