Visual prosthesis for control of spatiotemporal interactions

摘要

In a visual prosthesis or other neural stimulator it is advantageous to provide non-overlapping pulses in order to provide independent control of brightness from different electrodes. Non-overlapping pulses on geographically close electrodes avoid electric-field interaction which leads to brightness summation or changes in the shape and area of percepts. It is advantageous to apply pulses to nearby electrodes in a way that the currents do not overlap in time at all. ‘Nearby’ is defined as within a few millimeters of each other. The same parameters that provide independent control of brightness also produce spatial patterns that the subjects' report as being similar to the sum of individual electrode phosphenes. Simultaneous stimulation of multiple electrodes can sometimes produce physical sensation or discomfort in the eye. Time-shifting the pulses cab also be used to reduce the physical sensations felt by the patient.

主权项

1. A neural stimulator comprising:
a first set of electrodes suitable to stimulate neural tissue; a second set of electrodes suitable to stimulate neural tissue close enough to the first set of stimulating electrodes to cause electric field interactions at currents between 20 and 425 microamperes; a signal generator coupled to the first set of electrodes generating a first set of suprathreshold stimulation pulses suitable to induce a first set of percepts; and the signal generator coupled to the second set of electrodes generating a second set of suprathreshold stimulation pulses suitable to induce a second set of percepts, wherein the second set of stimulation pulses are phase shifted from the first set of stimulation pulses to minimize electrical field interactions between the first set of precepts and the second set of percepts.