皮質領野剔除の延滞条件反射に及ぼす影響

EFFECT OF ABLATION OF CORTICAL AREAS ON CONDITIONED DELAYED REFLEX

　1）誘発電位法及び変性実験によつて報告されている犬の聴覚領野並びに聴覚と密接な関係を有する皮質領野を部分的に又は一括して両側剔除し，聴覚性唾液条件反射を土台にした延滞条件反射の把持及び形成に及ぼす影響を経過を追つて観察した。

　2）予め20秒の延滞条件反射形成を行つた犬の聴覚領野並びにそれと密接な関係のある領野を遂次部分的に又は一括して別除すると，いずれの場合も術後強化実験を開始してから11乃至13系列目から術前値への回復がみられた。

　3）予め聴覚領野を広範囲に剔除した犬では20秒の延滞条件反射の形成過程は対照犬のそれと比較して殆ど差を示さなかつた。

　4）以上の結果により聴覚性延滞条件反射の形成及び把持には聴覚領野を含めたより広範囲な皮質領野が之に関与する事を推論し，更に之等の領野と延滞制止の発生について考察を加えた。

1) Four dogs with salivary fistula made by preliminary operation were used in this experiment.

One of them was used as a control. The others were subjected to partial or total abla-tion of the cortical acoustic areas before or after training them to the acoustic condition-ed delayed reflex (delay interval 20 sec).

2) The partial or total ablation of the cor-tical acoustic areas caused initial transitory shortening or unstable fluctuation of the de-lay interval which, however, regained its preoperative level after relatively short period (11-13 sequences of post-operative reinforce-ment).

3) The preliminary bilateral total ablation of the cortical acoustic areas had no remark-able effect on the establishment of the acous-tic conditioned delayed reflex.

4) From these results it was concluded that the more extensive sensory areas as well as associative areas must take part in the establishment and retention of the audi-tory conditioned delayed reflex. The under-lying mechanism for the generation of the inhibition of delay was also discussed.