視床下部情動機構の脳外科的考察

NEUROSURGICAL CONSIDERATIONS OF THE HYPOTHALAMIC MECHANISM OF EMOTION

I．はじめに

　行動がわれわれ臨床家にとつて問題となるのは，それが家族や社会にとつて大きな災厄をもたらす行動である場合で，その典型的なものが狂暴症とかviolent behaviorとかaggressive behaviorとかrage attackとかよばれている情動障害である。このような患者を鎮静ならしめ，家族や社会のうける迷惑をのぞき，さらに社会に復帰せしめることは脳神経外科医に課せられた重大な責務なのである。

　ところで鎮静を目的とする脳手術をくわだてるには行動の基底にある情動の機構についての洞察が必要である。従来の諸説やそれらのもととなつている諸実験，臨床経験については別の機会にくわしく報告した^11）12）のでここでは情動の機構に関するわれわれの作業仮説を述べるにとどめ，ついで視床下部に対する侵襲の臨床的ならびに実験的方面にうつりたいと思う。

The author believes that there are two functional circuits in the prosencephalon, the prosencephalic ergotropic circuits and prosencephalic trophotropic circuits. The integrated function of these two circuits is essential not only in autonomic activities, but in experience and expression of emotion. Aggressive behaviors or rage attacks can he regarded as the unbalanced condition of the circuits with dominance of the ergotropic circuits. In order to normalize the balance and to sedate the patient, it is necessary to produce lesions in the ergotropic circuits.

Based on this hypothesis, the author has performed anterior cingulectomy, thalamotomy, fornicotomy and upper mesencephalic reticulotomy. Sedative effects have been noted, on the average, only in 62 per cent of the cases. So the author chose, as the final target, the ergotropic zone of the hypothalamus which can be regarded as the central station of the ergotropic circuits.

This zone, where electrical stimulation produces signs of sympathetic discharge such as maximal pupillodilatation, tachycardia and rise in blood pres-sure, is found to occupy the postero-medial part of the hypothalamus. In the lateral view, it is located in a triangle formed by the midpoint of the AC-PC line, the anterior border of the mamillary body and the entrance of the aqueduct. In the antero-posterior view, it is located about 1~3 mm lateral to the lateral wall of the third ventricle.

Electrocoagulation lesions have been stereotactically made in this zone (postero-medial hypothalamotomy), bilaterally, in cases of aggressive behaviors or rage attacks (so far ten cases). Postoperatively marked calming effects have been noted without impairment of intelligence. There has been a tendency to decrease of sympathicotonia or increase of parasym-path icotonia

Electrophysiological findings during the postern-medial hypothalamotomy and the results of animal experiments (stimulation and destruction of various parts of the hypothalamus) are also reported and discussed.