neurophysiology: an INTEGRATION 



!959 



(Gernandt); and a given stimulus will lead to ex- 

 tension of a flexed leg, flexion of an extended one 

 (268). Indeed, the ability to use the same muscle 

 groups in a variety of coordinated acts, including 

 highly specialized learned skills, is almost a restate- 

 ment of the ability of a neural mass to transmit many 

 independent activation patterns. 



It is not necessary again to marshall evidence that 

 activity leaves behind some lowering of thresholds 

 and, therefore, makes learning possible; but it is 

 worth noting that feed-back controls into a mass of 

 neurons could themselves influence the amount and 

 locus of reverberating activity and so the character ol 

 enduring traces. Thus the influence of limbic and 

 brain-stem structures on recent memory is easily 

 understood. That 'good' outcomes reinforce behavior 

 and 'bad' ones extinguish it is solidly established, and 

 that particular brain regions are concerned in this is 

 becoming apparent. The frontal intrinsic area gives 

 direction and continuity to behavior (Pribram), 

 much as the discriminator postulated by Beurle. 

 Frontal temporal lesions are associated with loss of 

 signs of affect (MacLean), and lesions near the third 

 ventricle or of the cingulate gyrus may eliminate 

 'willing' (French). The whole question of attention is 

 obviously related and Livingston clearlv states the 

 view that the channeling of pathways by positive 

 reinforcement is the basis of values. 



Some direct evidence favors Beurle's theoretical 

 conclusion that where two waves meet the amount of 

 excitation is increased and may be more than doubled. 

 This is, in fact, the phenomenon of spatial summation 

 and subliminal fringe. It is exemplified by the ability 

 of a double maximal shock to the optic nerve to 

 produce a supermaximal response in the geniculate 

 (Bartley), time presumably being translated into 

 space. The regions of low threshold established by 

 repeated action of certain waves, the engrains, 

 constitute the internalized patterns derived from and 

 representing the external world (49) and also consti- 

 tute the encoded programs for behavior (Pribram). 

 It is highly relevant that evoked potentials in the 

 auditory cortex can trigger spontaneous waves of the 

 Lilly type (Ades), and that cortex waves do slow at 

 area boundaries (179), just as predicted by the 

 model. 



The final assumption, of internal feedback from 

 output to input, is at least suggested by the phe- 

 nomena of conditioning via direct stimulation of the 

 cortex, with no sensory input or observable behavioral 

 output in the process (Galambos & Morgan). While 

 .1 motor skill is being acquired, at first visual feedback 



is most important but later proprioceptive information 

 dominates (Paillard). One can "feel' oneself per- 

 forming a skilled act and accomplished musicians 

 •practice' playing a composition without moving a 

 muscle, and with a consequent improvement in 

 performance, by "felt" motor and proprioceptive 

 experiences. Similarly, linguists (140) postulate an 

 ongoing emission of internal language from a 'mar- 

 shalling yard' of words and grammar, and a con- 

 tinuous feedback into it of such verbal activitv — with 

 internal editing — the equivalent of E and I control of 

 repeating in a neuron mass. In conditioning, cortical 

 potential responses appear before motor behavioral 

 responses, and they endure longer during extinction 

 (20, 21). (Less clear is the falling out of cortex re- 

 sponses, with retention of motor ones, in sleep and 

 habituation. ) 



Such a model, built upon and supported by sound 

 neurophysiology, comes encouragingly close to 

 offering a workable and satisfying picture of neural 

 mechanisms of behavior. Thus, at the neuron and 

 neuron-group levels, neurophysiology and general 

 psychology are joining hands, just as, al the molecular 

 and organelle levels, biochemistr) and general phvsi- 

 ologv are doing likeu ise. 



Man's Luge and organized brain has enabled him 

 to receive and process information to an unparalleled 

 degree and, on the basis of this, to manipulate and 

 control his environment with great potency. Highly 

 structured communication between men, involving 

 the classification of experience, the distillation of 

 concepts from this and their formalization into a 

 coded language made possible the collective creation 

 of tools and machines, of tire and other energv 

 sources, of structures for habitation and production 

 and movement, of the institutions and aspirations of 

 a community, of the whole rich synthetic environment 

 of culture in which all civilized men are immersed. 



Mankind, operating in groups and societies, as 

 higher level systems or epiorganisms, has become the 

 great catalyst of evolution. Man, as all living things, 

 has consumed energy to decrease entropy and create 

 order or information. Man's numbers, his institutions, 

 his records and his knowledge are all increasing along 

 exponential curves. The latter, due to science, has 

 the shortest time constant, doubling every 15 years 

 since science began two and a half centuries ago (233 



