PROBLEM TO BE SOLVED: To provide an electrical stimulation signal control circuit which reduces potential variations of a microelectrode before and after an application of an electrical stimulation signal to a living body, applies the electrical stimulation signal, and detects bioelectrical signals accompanying the application of the electrical stimulation signal.SOLUTION: The microelectrode, an input amplifier, and a main amplifier are connected to have a state in which an adder circuit is separated from an electrical stimulation signal generating device in the normal time by a control means which controls an interface circuit connected to the microelectrode, the electrical stimulation signal generating device for applying electrical stimulation signals to the microelectrode via the interface circuit, and the main amplifier for amplifying the bioelectrical signals from the microelectrode via the interface circuit by a switch. Then, the microelectrode, the input amplifier, and the main amplifier are separated, and simultaneously, the electrical stimulation signal generating device and the adder circuit are connected. The potential retained in a direct current potential retaining circuit is amplified by a retained potential amplifier with an amplification factor which is the reciprocal of an amplification factor of the input amplifier, added to the electrical stimulation signal from the electrical stimulation signal generating device, and applied to the microelectrode.COPYRIGHT: (C)2010,JPO&INPIT【課題】生体への電気刺激信号の印加前後の微小電極の電位変動を小さくし、電気刺激信号を印加しそれに伴う生体電気信号を検出する電気刺激信号制御回路を提供する。【解決手段】微小電極に接続されるインタフェース回路と、インタフェース回路を介して微小電極に電気刺激信号を印加する電気刺激信号発生装置と、インタフェース回路を介して微小電極からの生体電気信号を増幅する主増幅器とを、制御手段によるスイッチの制御によって、通常時には、微小電極と入力増幅器と主増幅器とが接続され、加算回路と電気刺激信号発生装置とが切り離された状態とし、その後、微小電極と入力増幅器と主増幅器とを切り離すと同時に電気刺激信号発生装置と加算回路とを接続し、直流電位保持回路に保持された電位を、入力増幅器の増幅率の略逆数となる増幅率の保持電位増幅器によって増幅し、電気刺激信号発生装置からの電気刺激信号に加算して、微小電極に印加する。【選択図】図1
