Neural recording is one of the main issues to be addressed in order to allow closed-loop functional electrical stimulation systems. Because each fascicle in nerves carry specific information, new sensors providing high spatial selectivity are required for chronic implantable devices. This work aims at evaluating the feasibility of a new device using a highly spatial-selective multi-contact cuff electrode.
View Article and Find Full Text PDFMulti-electrode devices are constantly evolving toward a state where complexity and reliability are adequate for providing a breakthrough in visual cortical stimulation allowing the blind to recover partial vision. Yet few research teams have focused on the development of the front-end subsystem that transforms an input image from a camera into stimulation commands. This article collects state-of-the-art knowledge about the appearance and organization of phosphenes, and previous work in image processing dedicated to visual cortical stimulation.
View Article and Find Full Text PDFAn integrated microstimulator designed for a cortical visual prosthesis is presented, along with a pixel reordering algorithm, together minimizing the peak total current and voltage required for stimulation of large numbers of electrodes at a high rate. In order to maximize the available voltage for stimulation at a given supply voltage for generating biphasic pulses, the device uses monopolar stimulation, where the return electrode voltage is dynamically varied. Thus, the voltage available for stimulation is maximized, as opposed to the conventional fixed return voltage monopolar approach, and impedance is significantly lower than can be achieved using bipolar stimulation with microelectrodes.
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