PAIN 



497 



tion to all noxa to a sharply focal cerebral lesion has 

 dubious validitv. 



REACTIONS AFTER OPERATIONS ON FRONTAL LOBES. 



The modifications in the reaction of the individual 

 to painful or distressing states provoked by removal of 

 cortex or division of white fibers in the anterior two- 

 thirds of the frontal lobe remain to be considered. 

 Such lesions in an otherwise normal brain diminish 

 the general reaction to constant pain of organic cause, 

 such as advancing cancer, as well as the reaction to 

 such psychological suff"ering as may be occasioned by 

 the knowledge of impending death, an obsessive com- 

 pulsive psychoneurosis or psychotic agitated depres- 

 sion. But the price paid for such relief includes in- 

 ability to experience keen pleasure as well, i.e. there 

 is a flattening of all affect and the de\elopment of a 

 more or less apathetic state. In addition a wide variety 

 of evidences of mental deficit may appear. The 

 greater the area of frontal lobe removed or deprived 

 of its normal connections by division of white matter, 

 the greater the deficit. When most of the frontal white 

 matter of a normally functioning human brain is 

 transected bilaterally in the coronal plane just an- 

 terior to the lateral ventricles, there is often a serious 

 disturbance of intellect and personality, as described 

 by Rylander (234), Freeman & Watts (84, pp. 360 

 to 374), and Krayenbiihl & Stoll (146). In an oc- 

 casional patient these defects are mild enough to 

 permit the indi\idual to return to his work and 

 retain for years a useful degree of pain relief (84, pp. 

 367 to 368; 205, pp. 452 to 453). 



In an effort to secure a fruitful result with re.spect 

 to pain but to preserve the personalit\, small lesions 

 have been made. A total division of the white fibers 

 on one side only, according to Koskoff c/ al. (145) and 

 Scarff (235), produces a lesser deficit from which 

 there is usually much recovery, unfortunately accom- 

 panied pari passu by return of pain. No significant 

 difference in result re pain has been noted between 

 division of fibers contralateral or ipsilateral to one- 

 sided pain or between operations in the dominant or 

 nondominant hemisphere. Bilateral inferior quadrant, 

 bilateral medial or inferomedial lesions (i 1 1), removal 

 of various small portions of the frontal lobes 

 bilaterally, i.e. topectomy (216) or undercutting of 

 various parts of the frontal cortex (244) have all been 

 performed. Such patients have as yet been less thor- 

 oughly studied in relation to the correlation between 

 locus of lesion and relief of pain, but the general 

 pattern is similar in all. Contrary to the situation in 



pain asymbolia, the lobotomized patient's reaction 

 to individual noxious stimuli is, if anything, increased. 

 He jumps at pinpricks and needle punctures and 

 responds in the Hardy-Wolff-Goodell pain-threshold 

 apparatus by wincing and pulling his hand away at 

 a lesser stimulus after operation than before it, ac- 

 cording to Chapman et al. (41). The general experi- 

 ence amply confirms Freeman & Watts' observations 

 (84, pp. 371 and 372) that such events as rectal dila- 

 tation or childbirth are distressing to lobotomy pa- 

 tients. Moreover, following lobotomy when questioned 

 about their preoperative pain they are likely to state 

 that it is 'just as bad as ever' or "terrible." Yet they 

 ha\e few or no spontaneous complaints of pain, ask 

 for little or no medication even if narcotic addiction 

 appeared to be a problem before operation and are 

 far less miserable even when mentation is almost 

 normal. Patients with significant mental deficits may 

 deny pain on direct questioning or even forget about 

 the illness which is causing the pain. LeBeau (159, 

 pp. 134 to 135 and pp. 226 to 290} and White & 

 Sweet (296, pp. 287 to 333) summarize earlier reports 

 and give accounts of their own experiences. 



The behavior of the patients suggests that per- 

 sistence either of noxious physical stimuli or dis- 

 turbing thoughts sets off in the normal frontal lobes 

 a potentiating mechanism which becomes a major 

 factor in the total suffering of the person. That this 

 mechanism may be to some extent specific to the 

 frontal lobes is illustrated by the failure of bilateral 

 anterior temporal lobectomy to modify the reactions 

 to pain (296, p. 319). 



That the mechanism may involve the diffuse 

 thalamic projection system of Morison & Dempsey 

 (191) is suggested by the following experiments. The 

 thalamic nuclei of the macaque monkey giving rise 

 to this projection system are the .same ones which 

 recei\'e afferent impulses of .somatic and visceral origin 

 from the reticular activating system lying in the 

 medial brain stem (85, 254). These impulses are dis- 

 tributed in certain thalamic association nuclei mainly 

 to the frontal lobe anterior to areas 4 and 6. Magoun 

 and associates have suggested that it is disturbance 

 of the diffuse thalamic projection system which 

 diminishes the aff^ective component of sensorv per- 

 ception and deprives pain of its unpleasantness, the 

 characteristic state following a frontal lobotomy, 

 cortical undercutting or corticectomy. Since the 

 dorsomedial nucleus of the thalamus is one of the 

 main association nuclei for the diffuse thalamic 

 projection system this explanation would also account 

 for the similar condition following operative destruc- 



