The electrical interfacing of individual nerve cells and silicon microstructures is considered, as well as the assembly of elementary hybrid systems made of neuronal networks and semiconductor microelectronics. Without electrochemical processes, coupling of the electron-conducting semiconductor and the ion-conducting neurons relies on a close contact of cell membrane and oxidised silicon with a high resistance of the junction and a high conductance of the attached membrane. Neuronal excitation can be elicited and recorded from the chip by capacitive contacts and by field-effect transistors with an open gate. Integrated iono-electronic system are obtained by the outgrowth of neuronal networks on the surface of the silicon chip, by implementing electrical circuits in the chip and by two-way interfacing of the neuronal and the electronic components.