Fig. 3

Cochlear implant, demonstrating the variety of components of implanted neural interfaces. The magnets connect the external (left) and internal (right) units across the skin. The microphone on the external unit records sound, the sound processor converts the sound recordings to a digital signal with stimulation commands, the stimulation commands and power from the battery are sent from the external to the internal transceiver, the stimulation commands are converted into a stimulation output by the pulse generator, the lead wires carry the current to the electrodes, which generate an electric field that activates auditory neurons that lie outside the cochlea. Recording of impedance at the electrode-tissue interface can also occur, where the DAQ records the electrode impedance with reference to the ground electrode, and transmits these data to a different external transceiver to transfer the data to a computer for viewing by clinical team members