Embedded device for simultaneous recording and stimulation for retina implant research

Simultaneous stimulation and recording of retinal nerve cells with penetrating three dimensional multi-electrode arrays (MEA) on a localized area is a demanding challenge in next generation retina implant research. Within the scope of this research we developed a device to stimulate a network of bi-polar cells and record retinal ganglion cells with a slight time gap to overcome long recording dead times and switching artifacts in common stimulation- and recording systems. The device contains a four channel stimulator capable of pushing arbitrary bi-polar charges into the tissue and a 16 channel commercial electrophysiology interface chip. The device is a miniaturized front-end for our former developed embedded wireless communicating sensor node. First tests in in-vitro retina slices on adult rat with our device show reliable recordings of ganglia cell activity below 1ms after the bi-polar cell stimulation.