High resolution cortical imaging using electrolyte-(metal)-oxide-semiconductor field effect transistors

Brain-machine interfaces are currently based on techniques allowing either to record at high resolution from one or a few single neurons, or low spatial resolution recordings with a sparse sampling within the networks. To better interface to circuitries and to understand their role in sensory systems or cognition, higher resolution probes are required. In this paper we report a novel technique capable of recording cortical signals at a high resolution providing an electrical imaging of the cortical region under examination. Imaging was performed using two different types of electrolyte-(metal)-oxide-semiconductor field effect transistor, E(M)OSFET based multi-transistor arrays (MTAs): 1) 64 recording elements, integrated into a planar chip at high resolution (pitch: 30 μm-40 μm); 2) a matrix of 128 × 128 recording elements, integrated at a higher resolution (pitch: 7.4 μm, type: EMOSFET). These silicon micro-devices were capable of simultaneous recording of neuronal signals from the somatosensory cortex (S1) of the rat brain and were suitable in performing a real-time electrical imaging of the brain cortex in-vivo.