Jeudi 31 mai 2007
The lecture describes the electrical interfacing between semiconductor devices and living nerve cells. A physical understanding of these processes is important for applications of microelectronic chips in neurobiology and neuroprosthetics and also for experiments that may lead to neurocomputers. The structure and passive electrical properties of the cell-solid contact are investigated with luminescent dyes (wide angle interference & Stark effect). The electrical signaling from cells to silicon and from silicon to cells is studied with recombinant ion channels (Na+ and K+ channels) in cells that are cultured on electrolyte-SiO2-Si transistors and on electrolyte-TiO2-Si capacitors, respectively. On that basis, the stimulation of nerve cells from snails and rats by capacitors and the recording of neuronal activity with transistors is implemented. Two kinds of neuronal networks are interfaced with silicon chips : (i) small networks obtained by culturing neurons from snail and rat and (ii) large networks that preexist in the tissue of rat brain. The spatiotemporal dynamics of electrical signaling and memory formation in brain tissue is investigated by CMOS chips with closely packed arrays of transistors and capacitors.