264 Information Storage and Neural Control 



obtain milk once again elicited the same slow potentials in centralis 

 lateralis and elsewhere as seen previously in Figure 12. 



These observations seemed to support the interpretation that 

 the labeled potentials reflected some aspect of information process- 

 ing and might be of functional significance. Such an interpretation 

 would also be in agreeinent with the findings of Livanov et al. (13) 

 and Liberson et al. (12) who have reported that direct electrical 

 stimulation of various brain structures at frequencies like those of 

 the intermittent conditioned stimuli used in establishing a condi- 

 tioned response resulted in performance of the learned behavior. 



Nonspecific structures seem to play a central role in the processing 

 of information during differentiation. Evidence of differential 

 suppression of potentials after habituation, of the major signs of 

 assimilation, of the inost marked increinents in labeled potentials 

 during differential training, and of shifts in the frequency of 

 labeled potentials during behaviorally inappropriate response have 

 all been observed in these structures. The particular configuration 

 of potential patterns during differential response suggested several 

 hypotheses: 1) The role of specific sensory systems may be con- 

 ceived of as the central propagation of information representing 

 the present state of the environment to a particular cortical region; 

 2) this information may be compared, via the diffuse projection 

 system, with a representation of past experiences activated in the 

 rhinencephalon and the reticular formation by the similarity be- 

 tween past and present environment, modified by the state of 

 the organism in terms of effect and drive level; and, 3) the 

 appropriate selective performance of adaptive behavioral responses 

 may depend upon achievement of a sufficient congruence, via some 

 unknown coincidence detection mechanism, of the potentials 

 reflecting present and past experience. 



CONCURRENT PERIPHERAL AND 

 CENTRAL STIMULATION 



These various considerations led our group to investigate further 

 the question of whether temporal patterns of potentials might be 

 information. When animals are trained to perform a differential 

 discrimination between two flicker stimuli differing in frequency, 



