28 



Survey of Neurobiology 



lectivity of intracentral connec- 

 tions). 



3) Factors producing changes of 



specificity ( peripheral influen- 

 ces; serological effects; ageing). 



4) Neurosecretory processes (de- 



velopment of secretory functions 

 in neural cells; transformation 

 of neural into secretory cells). 



5) Myelinization (constitutional dif- 



ferentials between medullated 

 and unmedullated fibers; role of 

 sheath cells; role of functional 

 activity ) . 



D. Quantitative development of the ner- 

 vous system. 



1 ) Determination of number of gang- 



lion cells (rate of proliferation; 

 rate of specialization; mitotic 

 control; cell migration; degen- 

 eration; replacement; sex and 

 species differentials; effect of 

 function on cell number; effect 

 of peripheral connections; hor- 

 mone effects). 



2) Density of nerve nets (number of 



collaterals; distribution of end- 

 feet; relation between neuropil 

 and glia; saturation factors). 



3) Growth and size of neurons (con- 



stitutional vs. exogenous factors 

 in cell size; protein synthesis; 

 functional and trophic effects 

 on cell size; nutritional in- 

 fluences; determination of fiber 

 caliber; limitations of growth 

 capacity; length of neurites; de- 

 velopmental metabolism ) . 



E. Formation of nerve patterns. 



1) Orienting factors (direction of 



outgrowth; plexus formation; 

 "attraction"; pathways; electric 

 influences; neurotropism). 



2) Elaborating factors (aggregation; 



bundle formation; branching; 

 resorption; neuromas). 



F. Vascular development. 



Relations between nervous system 

 and blood and lymph systems 

 (vascular pattern; functional 

 adaptation to varying oxygen de- 

 mands; nutrient channels; edema). 



G. Regeneration ami regulation. 



1 ) Peripheral nerve regeneration 

 (Wallerian degeneration; axon 

 regeneration; sheath cell transfor- 

 mations; growth rate; effects of 

 age; inhibiting factors; nerve su- 

 ture; traumatic vs. spontaneous 

 regeneration; differences among 

 different nerves; nerve transplan- 

 tation). 



2) Regeneration in the central ner- 

 vous system (differences accord- 

 ing to species and age; role of 

 ependyma and glia; tumors; syn- 

 aptic rearrangements; transplanta- 

 tion of ganglia, brain and spinal 

 cord ) . 



3) Non-regenerative regulation 

 ( compensatory adjustments of 

 centers after injury). 



4) Metamorphosis (morphological 

 and functional transformations in 

 postembryonic stages; hormonal 

 determination; maturation prob- 

 lems). 



H. Trophic ejects of nervous system. 



(Regulation of tissue growth and 

 maintenance by neural factors; 

 causation of atrophy and hyper- 

 trophy; effects on lymphocytosis, 

 capillary permeability, immune 

 reactions ) . 



I. Development of behavior. 



1) Origin of reflexes (coordination; 

 role of input; localization vs. mass 

 action ) . 



2) Development of integrative mech- 

 anisms. 



3) Development of central automa- 

 tisms (rhythmic activities; meta- 

 bolic cycles). 



4) Plasticity (homoeostasis; learning; 

 compensatory mechanisms ) . 



K. Genetic aspects. 



( Inheritance of neural and behavioral 

 traits; genetic aberrations). 



NEED 



The need for intensified and methodical re- 

 search in genetic neurology is documented 

 by the inadequacy of many of the current 

 basic concepts of the mechanics and phys- 



