嗅球の中枢性支配
その一 扁桃核および前交連前肢の刺激の影響について
1962 年 12 巻 6 号 p. 431-441
詳細
1962 年 12 巻 6 号 p. 431-441
1. By means of eletrical stimulation of the amygdala, the anterior limb of the anterior commissure and the mesencephalic reticular formation, the centrifugal influences of these areas upon the potential wave evoked by the electrical stimulation of the olfactory epithelium (A-wave) were studied in the rabbit.
2. When a single electric shock was applied onto the medial part of the amygdala, monophas ic or diphasic negative wave appeared in the bulb. It did not show an effect upon the A-wave which may suggest a true inhibition. When a single shock was applied onto the lateral part of the amygdala, a diphasic potential which is a small electro-negative wave followed by a large positive wave of about 70 to 80 msec appeared in the olfactory bulb. The A-wave decreased its amplitude for 600 to 800 msec after the appearance of the above potential. From the shape of the potential, the magnitude and length of the influence of the potential upon the A-wave and the histological finding of the bulb, It was concluded that there is an inhibitory tract to the olfactory bulb from the lateral part of the amygdala.
3. Single or repetitive stimulation of the mesencepalic reticular formation did not show any effect upon the A-wave. However, when the lateral part of the amygdala was repetitively stimulated together with the above stimulation, the inhibitory effect which was produced only by the former stimulation was strikingly elongated. Consequently, it was supposed that the centrifugal control of the olfactory bulb depends upon the excitatory state of the cerebrum.
4. The electrical stimulation of the anteri or limb of the anterior commissure did not show any inhibitory effect upon the A-wave. The same negative result was obtained even when the stimulation of the mesencephalic reticular formation was simultaneously applied.
5. Single shocks were applied onto various points in the intermediate part of the cerebrum between the olfactory bulb and the amygdala, and the fibers from and to the olfactory bulb were sought. The potential waves evoked in the bulb by this way were compared with those evoked by the stimulation of the amygdala. From the similarity of the potential shapes, the sites of recording and the histological finding, it was concluded that the Inhibitory tract from the amygdala to the olfactory bulb runs just above and in parallel with the lateral olfactory tract and reaches the granule cell of the olfactory bulb.
