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II VXDIil it IK I 11 I'llVMl il i IG1 



NliLROrllYSlOLOGY III 



replace the slow and less dependable junctions. Speed 

 and precision have been eschewed tor richness and 

 variability, and the nervous system has gained 



freedom I km ween stimulus and response in time, 

 intensity and pattern. 



system properties. At each level of living systems, 

 from membrane through neuron to brain and group, 

 and lor nonliving simulacres, from torpedo to com- 

 puter, then- jure, then, certain organization and action 

 properties, lor each, it is important to work out the 

 architecture, to identify significant units, and to 

 trace the kind, and patterns of their interrelations. 

 For each, il is important to examine the How, particu- 

 larly ol information, and the mechanisms lor coding, 

 storing and utilizing it. lor each, the self-regulating 

 and sjoal-scckim; activities must he identified, and the 

 decision-makim; processes analyzed. 



The problems of neurophysiology thus resolve 

 themselves into the properties of the individual units 

 and the mechanisms and patterns of interaction of 

 these units, into the dynamic attributes of the synap- 

 tic system and into the mechanisms of interaction of 

 masses of neurons. The problems of physiological 

 anatomy of the nervous swem become those of the 

 actual table of organization the degree of centrali- 

 zation relative to local autonomy underlies the 

 decision-making sequences (a sort of functional 

 topology) and provides the functional significance of 

 the actual spatial disposition of neuron clusters and 

 interconnections, finally, anatomy and physiology 

 merge in neurochemistry at the level of molecular 



architecture and traffic. In the following sections, the 

 nervous system will be examined from such view- 

 points. 



X, ural Evolution 



COMPONENTS. A vcasl cell and a cortical neuron 

 contain many interchangeable complex molecules 

 and engage in highly similar chemical changes. The 

 basic metabolic paths and pools are alike, so that the 

 processes underlying dynamic equilibrium or main- 

 tenance have not changed importantly during evolu- 

 tion. Similarly, lor the patterns and mechanisms 

 underlying specific synthesis, the genetic and other 

 synthetic processes have been carried forward from 



microbes to mammals I Ins is not so lor adaptive 



plification, the handling of information, and the 

 repertoire oi experiencing, integrating, .mil behaving. 

 1 trganisms air rated from low to high on a scale thai 

 roughly his the richness oi behavior which parallels 



the development ol the nervous system. If living 

 differs from nonliving in having learned to manipulate 

 energy, as man with fire is to man without, then the 

 higher animals differ from lower organisms in having 



learned to handle information, as culture with 

 language is to life without. 



Starting with familiar molecules in relatively 

 simple patterns, animals have invented new substances 

 and created intricate organizations so that their 

 capacities lor using information have increased 

 explosively. The reacting elements of reception, 

 conduction and transmission, and response wen- 

 pretty much perfected early in evolution. Regularly 

 layered molecules, able to generate oriented poten- 

 tials, are alike responsible lor reception, as in rods 

 (Wald); for conduction, in nerve fibers, and trans- 

 mission, as in the junctional generator potentials set 

 up in end plates (Fatt) and presumably in post- 

 synaptic membranes; .mil lor responses, as of muscle 

 libers and electroplaques. Such basic elements seem 

 to have reached their full development with the 

 appearance of vertebrates and arthropods (e.g. 

 Autrum). The human eve may be a better all-round 

 instrument (llartlinei, but it is not sensitive to ultra- 

 violet or polarized light nor is it able to resolve high 

 speed movement, as are some insect eyes, and it has 

 poorer nocturnal vision and acuity than other 

 vertebrate eves. The pit viper has a better temperature 

 sense; the bat, a wider range of hearing; the dog, a 

 superior sense of smell; various fish, .1 belter taste 

 and an electrical sense; birds, superior cues for orien- 

 tation; and so on. The nerve impulse, the synaptic 

 mechanism, the muscle machine are essentially alike 



in frog and physiologist. Nevertheless, mammals 



excel their humbler relatives in the range, sensitivity, 

 discrimination and capacity in receiving information 

 from their environment; and in the speed, control and 

 repertoire of their behaviors in responding to such 

 information. This advance results from superior 

 patterns in the array of the same elements of the 



svsiem [cf. Gerard 1 1 12)]. 



PATTERNS. A vasi improvement in performance of 

 given elements can be achieved by small improvement 

 in their patterning. Feed-back loops thai control 



receptor sensitivity and inflow channel volume, 

 similar loops that regulate and modulate motor 

 performance, other regulating elements thai direct 

 attention or set motor goals, as the gamma motoi 



fibers on muscle spindles, and intrinsic re-entrant 



loops and assemblies (Jung & Hassler) thai permit 



the shifting ol time relations and allow the recent 



