System for multichannel recording of the electrophysiological activity of a brain tissue in-vivo

In this paper we present a measurement system for multichannel recordings of the electrophysiological activity of brain tissue in vivo. The system consists of: penetrating Microelectrode Array (MEA), three versions of a Conditioning Module each equipped with different Application Specific Integrated Circuits (ASIC´s), Digitizer and PC Application for recorded data presentation and storage. The MEA consists of 64 15 μm diameter microelectrodes. The multichannel ASIC´s amplify and filter field and action potential signals. The custom-made Digitizer Module simultaneously acquires data from all channels with a 14 kS/s sample rate and 12 bit resolution. The resulting byte stream (about 2 MB/s) is transmitted to the PC via USB (Universal Serial Bus). Eventually the measurement data is decoded, presented to the system user and stored on a HDD. Preliminary in-vivo measurements confirm that the system is capable of a multipoint recording of action potentials with amplitude down to 50uV.