Neural Mechanisms of Decision Alaking 279 



detection, in whicli things could be compared in the same coin. 

 I believe that the coin in such networks might be the spatio- 

 temporal distribution of electrical activity. 



It is at this point that your second question becomes relevant. 

 You are really asking, "Can such encoding be possible for any- 

 thing other than the very artificial situation which we have 

 devised? Can the temporal pattern of electrical events really be 

 suggested for the representation of stimulus configurations which 

 are not characterized by particular frequencies of events? Could 

 a temporal pattern of neural potentials represent stimulus fre- 

 quencies above the range of EEG rhythms?" I think this is clearly 

 possible. One could conceive of spatio-temporal transforms so 

 that a characteristic distribution of simultaneous events in dif- 

 ferent regions of the brain would generate a characteristic se- 

 quence of temporal events at soine loci. Spatial distributions 

 can be transformed to temporal patterns, and temporal patterns 

 can be transformed to spatial distributions. Projection pathways 

 of different lengths and diflferent propagation velocities could 

 conceivably project a characteristic representational temporal 

 pattern which would correspond to the distribution of simultaneous 

 excitation in anatomically dispersed areas of a neural population. 

 Representational patterns need not be isomorphic with that which 

 they represent. 



Your question also relates to parsimony, which I do not con- 

 sider to be a law of nature, but which is a help in the intuitive 

 ordering of probabilities. Admittedly, the conditions which we 

 use in our experiments are artificial, and deliberately so. Cats 

 live in a world containing more information than simply the 

 frequencies of flickering lights. We hope that this artificial situ- 

 ation might give us some insight into the processing of information. 

 However, once one reaches the conclusion that information about 

 this carefully constrained and defined environment may be handled 

 by mechanisms related to the temporal patterning of electrical po- 

 tentials, a problem arises. If one wants to postulate a diff'erent mech- 

 anism for coding other kinds of sensory information, one has 

 introduced chaos into the nervous system. Rapid and accurate 

 integration seems more compatible with a system which codes 

 all data in one language and decodes it in the same tongue than 



