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Neurostimulateur multiple à impulsions rectangulaires et sorties isolêes

par Cerf, Jean ;Libert, Charles
Référence Electroencephalography and clinical neurophysiology, 7, 3, page (433-437)
Publication Publié, 1955-08

Article révisé par les pairs

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Résumé :

The paper describes a multi-channel stimulator delivering the following electrical siǵnals through separate outputs: (a) two brief rectangular pulses of variable duration, separated by a chosen interval; (b) repeated (tetanizing) pulses of variable frequency and train-duration; (c) a d.c. polarizing stimulus of variable duration. A built-in trigger circuit, hand-controlled or self-firing at a chosen frequency, delivers positive pulses driving the sweep of a ccthode-ray oscillograph used in connection with the stimulator. The same pulses trigger the different circuits generating stimulating signals, each through a separate delay unit introducing a measurable time lag. Thus, proper delay adjustment in each channel enables synchronisation with the oscillograph sweep of the various available electrical stimuli, delivered in any desired sequence. A versatile rectangular-wave generator has been designed, and extensively applied to the entire apparatus construction. This basic circuit assumes every stage operation (trigger stage; stimulus delay, frequency, and duration stages); with minor adjustments it is made to work, according to each function, either as a one-shot or as a free-running multivibrator. Exclusive use, in the stimulator design, of similar units greatly simplifies construction and servicing. Moreover, owing to the symmetrical operation of these circuits, the power supply has a constant load and must not be regulated. Each channel of the stimulator is linked to the physiological preparation through a radiofrequency coupling. The pulses from the output stages are the source of plate power for H.F. oscillators, and the radio oscillations produced transmitted to receiver coils. The induced voltages, demodulated and filtered, reflect the original signals from each channel but are electrically isolated. © 1955.