COORDINATION 425 



wise, there is a ■wide variation in the size of pathways can sometimes be broken up and 



brains of different individuals of the same new, more compatible ones be established, 



sex, just as there is in stature and body A more drastic treatment is actually to cut 



weights. Famous brains have been pre- across the pathways in the prefrontal lobe 



served and weighed, out of morbid curiosity of the cerebrum. It is too early to predict 



or for scientific purposes, and it has been how effective this type of treatment will be. 



shown that a variation of 800 grams exists The medical profession is learning that 



between brains of apparent equal intelli- more and more of the common ailments of 



gence. So, within limits, brain size alone is mankind are due to an overactive cerebral 



not a criterion of intelligence. Intelligence cortex rather than actual organic disease; 



is probably due to such things as the num- that is, people imagine they are sick, and 



ber of cell bodies or the number of associa- this can be carried so far that actual symp- 



tion neurons in the cortex of the cerebrum toms from heart disease to stomach ulcers 



which, in turn, is an indication of the num- are present. This has resulted in a new field 



ber of pathways over which impulses may of medical research known as psychosoma- 



travel. tic medicine. With proper treatment, certain 



The two cerebral hemispheres are each neurotic tendencies can be overcome and 



divided into five lobes and the nerve cells the person miraculously "cured." This type 



associated with various functions are local- of medical research is commanding increas- 



ized in these lobes ( Fig. 16-22 ) . The center ing attention and holds hope for a different 



for sight is located in the occipital or pos- approach to the study of certain diseases, 

 terior lobe. Areas for smell, hearing, and 



taste are located in the lateral or temporal '^^^ autonomic nervous system 



lobe, while centers for muscle movements A great many activities of the body such 



are centered in the anterior or frontal lobe, as peristaltic movement in the intestines. 



Skin sensations lie in the parietal lobe. The breathing, and heart action go on unnoticed 



fifth lobe ( insula ) lies beneath the frontal and without voluntary control. These are all 



and parietal lobes and cannot be seen from under tlie influence of the so-called auto- 



the surface view. Large areas of the cortex nomic nervous system. The name implies 



are spoken of as "silent areas" because it that the system is a completely automatic 



appears that injuries to tliese regions result one, which is not the case, but it has become 



in no particular loss of sensory or motor fixed by usage. 



function. These are the great unknown areas Anatomically, part of the autonomic nerv- 



of the brain which have stimulated so much ous system can be seen as two rows of gan- 



research in recent years. glia ( lateral sympathetic ganglia ) lying on 



The complex life human beings live in each side of the spinal column in the tho- 

 modern society has produced extremely in- racic and abdominal cavities. The ganglia 

 tricate nerve pathways in the cerebral cor- are secured to the spinal nerves by means 

 tex, and in a so-called normal person these of two short connectives, a white and a 

 pathways are so arranged that he gets along gray ramus ( Fig. 16-23 ) . Distally they ex- 

 well under normal conditions. During times tend as small nerve fibers to the various 

 of great stress, these pathways sometimes organs of the chest and abdominal regions, 

 become so warped as to disqualify the indi- The incoming ( afferent ) fibers pass through 

 vidual for life in society. As a result, he the dorsal root just the same as the volun- 

 must be confined to an institution. It has tary nerve fibers, and the cell bodies are 

 been found that by subjecting such a per- located in the dorsal root ganglion. The 

 son to severe shock by means of insulin, notable difference between the two systems 

 electricity, and other agents, these aberrant is that the efferent fibers of the autonomic 



