Sensitive and selective neural control using an intraneural multielectrode stimulation device in silicon technology

The ideal neural stimulatory information transducer must be able to activate individual neural fibers within a fascicular bundle, for example in a sensory or motor nerve. In a local approach using microelectrodes it is sufficient to apply current pulses to one neural node in order to reach the stimulatory threshold of the so-called activating functions. To this end, a multielectrode array in silicon technology is being inserted into a fascicle. It is one out of several possible approaches using silicon technology. This report focuses on the sensitivity and selectivity of such a neuro-electronic interface, using monopolar cathodic stimulation pulses at one or two electrodes. A test for selectivity has been developed, using refractory properties. One conclusion is that beyond an electrode separation of 250- mu m, selectivity becomes maximal.