High-density microelectrode arrays for electrophysiological activity imaging of neuronal networks

Presents a new approach to high-density microelectrode arrays for spatially and temporally resolved images of in-vitro neuronal network electrophysiological activity. Based on active pixel sensor technology (APS), the first chip design consists of an array of 64 /spl times/ 64 (4096) pixels on an active area of 2.56 /spl times/ 2.56 mm/sup 2/. Each pixel has a dimension of 40 /spl times/ 40 /spl mu/m/sup 2/ integrating a gold microelectrode of 20 /spl times/ 20 /spl mu/m/sup 2/. An in-pixel differential amplifier locally amplifies the extracellular potential, minimising the electrode-measuring circuit distance. The integrated circuit has a programmable gain and filtering for noise-speed trade-off. The network activity image is obtained by addressing the desired pixels at high sampling frequency and sequentially reading the chip output.