Neuroanatomy — Sam L. Clark 



17 



connections in lower animals there com- 

 monly appear references to exteroceptive 

 fibers from various sources, and even gus- 

 tatory fibers, that enter the cerebellum; but 

 as soon as the description of the situation 

 in higher vertebrates is encountered ref- 

 erence is made only to proprioceptive con- 

 nections. Only recently evidence that tac- 

 tile, auditory, and visual impulses reach 

 the cerebellum has been published, and 

 even some evidence that the cerebellum 

 is not entirely free from relation to pain 

 and to visceral control has been brought 

 forth. 



On the afferent side to the cerebrum 

 there is still some question as to the rep- 

 resentation of pain in the cortex, so that 

 the site of termination of this important 

 pathway is not known. The exact course 

 and termination of most ascending path- 

 ways could be better understood. There 

 is need of further knowledge of the intri- 

 cate interconnections of parts of the gray 

 masses within the cerebrum, i.e., basal 

 ganglia; and thalamic, subthalamic and 

 hypothalamic nuclei. The large mass of in- 

 ternuncial connections in cord, brain stem, 

 and suprasegmental areas offers endless 

 possibility for investigation, as emphasized 

 by the significance of the reticular system 

 to general problems of inhibition and ex- 

 citation shown by Magoun and others. 



On the efferent side, even that pathway 

 most often discussed, the pyramidal, or 



cortico-spinal tract, needs further inves- 

 tigation. Due to the persistent and syste- 

 matic efforts of Lassek in recent years it 

 has been shorn of its simplicity until now 

 it is known to be not a specific path from 

 Betz cells to anterior horn cells, but a 

 collection of paths of at least diverse origin, 

 perhaps of diverse destination. There is 

 still debate about the very existence of a 

 rubro-spinal tract in man, and the great 

 number of "extra-pyramidal" pathways still 

 resists analysis. Descending paths for vis- 

 ceral control are almost completely un- 

 known, though some knowledge of the 

 ones concerned with the control of sweat 

 glands has lately been obtained. 



PERSONNEL 



For any and all developments in neu- 

 roanatomy new students are needed. Most 

 investigators in the field are attached to 

 departments of biology in universities and 

 to the departments of anatomy in schools 

 of medicine. However, only a small por- 

 tion of the graduate students and staff of 

 these departments becomes related to neu- 

 roanatomy. Fellowships and adequate fi- 

 nancial support for teachers and investiga- 

 tors directed toward the neurobiological 

 field would do much. Support for projects 

 in research is more readily obtained today 

 than support for men in training, and the 

 real need in this as in other fields is for 

 trained men. 



