THE ANTERIOR OR FRONTAL ASSOCIATION CENTER 649 



The Anterior or Frontal Association Center. The frontal area is 

 more closely connected with the motor areas and the centers for the somes- 

 thetic sense. With injury to this area the individual shows weakness in at- 

 tention, in reflection, and in control over the expressions of anger, self- appre- 

 ciation, and other activities that are expressive of personal volitions and 

 emotions. 



The American crowbar case is a classical instance of lesion of the frontal 

 lobe. A young man of twenty-five had an iron bar, an inch and a quarter 

 in diameter and over three feet long, driven through his skull and brain 

 by the premature explosion of a blast of powder. He not only recovered, 

 but lived for twelve years afterward. At the post-mortem examination the 

 puncture was found to be through the prefrontal lobe, anterior to the coro- 

 nal suture. 



This man was considered a most efficient workman and foreman before 



FIG. 407. The Association Fibers in the Centrum Ovale. A, Between adjacent con- 

 volutions; B, between frontal and occipital lobes; C, between frontal and temporal lobes, 

 the cingulum; D, between temporal and frontal lobes lesion of this tract causes paraphasia; 

 E, between occipital and temporal lobes lesion of this tract causes word-blindness; C.N, 

 caudate nucleus; O.T, optic thalamus. 



the injury. After his recovery he was fitful, impatient of restraint, capri- 

 cious, obstinate. He was most inconsiderate of his associates, profane and 

 passionate. From a shrewd business man he was changed to the intellectual 

 level of a child and was regarded by his associates as mentally unbalanced. 



A summary of fifty cases of pathological lesions of the prefrontal areas of 

 the human brain is given by Williamson. The mental traits of thirty-two are 

 summarized in the following terms: "A condition of mental decadence; a 

 dull mental state; loss of power of attention; loss of memory; loss of spon- 

 taneity; the patient takes no heed of his surroundings; sleeping during the 

 greater part of the day, or remaining semi-comatose." Yet these patients 

 are able to walk about and execute well co-ordinated muscular activities of 

 all kinds that do not involve complex intellectual activity. 



