大脳皮質の反復刺激によるDendritic potentialとDC shiftの研究

　Chang^1）が大脳皮質を直接刺激してその近傍から得たdendritic potential（DP）は微小電極による皮質内neuroneのspike pot．と共に脳の電気現象を理解するのに重要視されるに至つている。

　併しDPが果してapical dendritsの活動性を忠実に表現しているか否かについては何とも云えない段階にある。茲に於て著者等はDP以外にDC pot．の変化を記録してDPの性格特にその興奮部位を明確にせんと試みた。

　The dendritic potential (DP) and DC shift changes were produced at the surface of the cortex by the repetitive stimulation. Experiments were carried out in guinea pigs under light urethane anesthesia.

　The changes in DP and in DC shifts produced have been examined by varying the frequ-ency and intensity of stimulation. Stimulation at frequencies of 20~50c/s gives rise to surface-negative DC shifts which are sustained for the period (1sec.) of the repetitive stimulation. They were usually low in voltage, reaching the range between 1~2 mV at 50c/s. With increasing intensity of stimulation, the amplitude of the DC shift increased progressively.

　The most striking change in DP was the complete abolition of negative DP and also an appearance of the positive potential. The nature of the DC shift changes and their rela-tionship with the polarity of DP are discussed.