Neural Mechanisms of Decision Making 281 



cell differ, such ion-induced changes in template might accom- 

 plish increases or decreases from the usual rate of protein synthesis. 



In this view, macromolecular specificity is relevant only insofar 

 as the control of synthesis rate is concerned. The synthesized 

 material, no matter what its specific configuration, simply binds 

 charge. The presence of bound charge in some cellular regions 

 causes an inhomogeneous distribution of diffusible ions. The pro- 

 portion of diffusible to bound charge need not be the same every- 

 where within a cell nor from cell to cell. Consequently, the 

 equilibrium concentration for diffusible potassium is altered, the 

 rate of restoration of membrane polarization after discharge is 

 variable, the RC constants are different, and the interspike 

 intervals are different. By such a mechanism, this population of 

 cells which sustains reverberation could be shifted away from the 

 population mean with respect to the interspike interval and 

 become isolated. 



A mechanism of this sort seems to provide a way to get around 

 some of the severe problems which face a memory mechanism 

 based on protein specificity. For example, if memory were a 

 particularly specified macromolecular configuration, what would 

 protect it once it was built? Further, if RNA structure is at the 

 mercy of every influence which impinges on the cell, if you can 

 make many kinds of RNA depending on the afferent stimulus 

 configuration, then how does a cell sustain the enzymatic activity 

 necessary for its survival? Why assume that you can make any 

 kind of RNA or any kind of protein or enzyme? Why not assume 

 that the cell can make only stipulated kinds of macromolecules 

 with a facilitation mechanism of the sort I suggested regulating 

 the amounts of each? Such macromolecules could play many 

 roles, including that of binding charge. There is no specific macro- 

 molecular sequence which requires protection to preserve memory. 

 One cannot prevent the cell from being excited to enable memory 

 to be preserved. Why not assume that the protection is achieved 

 by randomness? 



A memory of the sort I describe here could be perturbed only 

 by a sustained nonrandom influence which impinged on a sub- 

 population of the coupled assemblage of cells mediating a memory, 

 and only if that influence were sustained long enough to alter 



