Neuroanato77iy — Sam L. Clark 



11 



used in ordinary speech, "sympathetic," 

 becomes in neuroanatomical nomenclature 

 a symbol of confusion and antagonism un- 

 less it is properly modified by phrases 

 which would be quite adequate alone. 



It is difficult to do anything about term- 

 inology already established, but the christ- 

 ener of newly described structures should 

 proceed with caution, and perhaps hesi- 

 tate over the selection of even an accurate, 

 purely morphological designation if it is 

 so complicated that only the mnemonically 

 minded student can retain it (e.g.: nucleus 

 ventralis posteromedialis of the lateral tha- 

 lamic nucleus). 



COMPARATIVE ANATOMICAL NEUROLOGY 



Admitting that "the proper study of man- 

 kind is man" there is yet much to be 

 learned about him by study of a compara- 

 tive series of the nervous systems of ani- 

 mals. It has been stated, that the best 

 known animal is the earthworm, but all 

 the details of the nervous system of this 

 animal are not clear. Significant studies 

 on the nervous svstcm of various inver- 

 tebrates and of fishes, amphibians, reptiles, 

 birds and mammals have been carried out, 

 but it is safe to assert that not all the de- 

 sired details in any one animal species have 

 been discovered. There is need for further 

 correlation of activity (behavior) with the 

 neuroanatomy and neurophysiology of each 

 of those animals commonly worked with 

 and for extending the observations to other 

 appropriate forms. For example, the brains 

 of bees and ants would seem entirely in- 

 adequate to account for their complicated 

 but well organized behavior. Experiments 

 correlating the structure of the brain in 

 these forms with their activities would be 

 of great importance along with other prob- 

 lems among invertebrates. A type of ap- 

 proach already applied in higher verte- 

 brates, that of removal of parts of the brain 

 and observation of the effects on resultant 

 activity, might be of value in these lower 

 forms and could be used more extensively 

 in lower vertebrates as well. Perhaps high- 

 ly complex instinctive reactions such as the 

 nesting habits of birds could be analyzed 

 by such means. 



The approach by means of experimental 

 embryology now being so well used with 

 salamanders and with chicks to explain 

 the basic principles of development should 

 be applied to more species. 



Correlation of normal developmental 

 changes in the nervous system with the 

 earliest appearance of behavior patterns 

 as has been done for amblystoma by Cog- 

 hill and his followers, for the cat and rat 

 by Windle and his students, and for man 

 by Hooker and others should be continued 

 and extended to other forms. In man closer 

 study of postnatal behavior in relation to 

 maturation and growth of the cerebral 

 cortex is indicated. 



In the vertebrates comparative methods 

 of study have made clearer the patterns 

 of cranial nerve components, the connec- 

 tions and significance of tracts and centers, 

 and the significance of suprasegmental 

 structures, cerebellum, tectum, and cere- 

 bral hemispheres, but the fields are not 

 entirely harvested. In comparative studies 

 of the gross anatomy of the cerebellum the 

 observations of Tilney and of Larsell cor- 

 relating the relative size of different por- 

 tions of the cerebellum with the relative 

 masses of muscle of different body parts 

 have supported localization of representa- 

 tion in the cerebellum, but further work of 

 this kind and its correlation with physio- 

 logical studies of the living animals is 

 needed. 



The relative position of gyri and sulci 

 of the cerebrum and their development in 

 different mammals has aided in interpret- 

 ing localization of function of the cortex, 

 but this type of analysis, on a gross ana- 

 tomical level, is not yet fully exploited. Even 

 the significance of the foldings of the cere- 

 bral and cerebellar cortex is unknown. The 

 lack of correlation of cytoarchitectonic 

 areas and gross subdivisions offers a field* 

 for further investigation. 



The external gross anatomy of man's 

 nervous system would appear to be ade- 

 quately known, and the greatest needs do 

 actually lie in this field in better descrip- 

 tions of brains of other animal species; 

 but there are those who emphasize the 

 possibility of further results to be gained 



