An Implantable Microsystem for Wireless Multi-Channel Cortical Recording

Abstract

This paper reports a 64-channel microsystem for chronic neural recording. The system scans all the channels simultaneously, detects any neural spikes, and reports their occurrence wirelessly to the external world. Any one of the selected channels can also be digitized and read out wirelessly to allow inspection of the full analog waveform. The neural signals are amplified with 60dB of gain, a programmable bandwidth, and an 8 &3x003BC;V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> input-referred noise level before being processed digitally. For a 2MHz clock, the channel scan rate for spike detection is 62.5kS/Sec and the total system power dissipation at 1.8V is 14.4mW. The implantable version of the microsystem weighs 275mg and measures 1.4cm×1.55cm.