In recent years it became conceptually feasible to study small networks of synaptically interactive neurons in vitro. Input (stimulation of a single neuron) and output (recording of electrical signals from individual neurons) control in such a neural network could be achieved by direct coupling of the neural electrical signals to a field-effect transistor (FET) device and metal microelectrodes, opening up the possibility for two-way, nontoxic communication between chips and nerve cells. However, the cell-device coupling is not very well understood and the control of this coupling challenging. An extracellular recording system has been designed for the detection of electrical cell signals.@footnote 1@ A field-effect transistor (FET)@footnote 2@ array has been fabricated which consists of p-channel or n-channel FETs with non-metallized gates. The size of the gates of the 16 FETs are from 16x3 um2 down to 5x1 um2 and are arranged in a 4x4 matrix on 200 and 100 um centers. On the other side extended gate electrode (EGE) arrays were used which are arranged in a 8x8 matrix on 200 and 100 um centers. The gate electrodes are made from gold, titanium and silicides with diameters down to 6 um. The cell-device coupling has been studied using various cell types e.g. neuronal cells, cardiac myocytes, and cells from cell lines. The recorded signals will be discussed on the base of a point contact model where contributions from passive as well as active membrane properties are included. @FootnoteText@ @footnote 1@ C. Sprössler, D. Richter, M. Denyer, A. Offenhäusser, Biosens.& Bioelec. 13, 613-618 (1998). @footnote 2@ A. Offenhäusser, C. Sprössler, M. Matsuzawa, W. Knoll, Biosens.&Bioelec. 12, 819-826 (1997).