A new method for long-term recording and stimulation applicable to cultured neurons has been developed. Silicon-based microelectrodes have been fabricated using integrated-circuit technology and micromachining. The chronic connection is made by positioning the electrode tip into contact with the cell body, and gluing the device to the bottom of the culture dish. These "diving-board electrodes" consist of an insulated lead exposed only at the tip sealed to the cell body of a cultured neuron. A two-way electrical connection to Helisoma B19 neurons has been established for up to four days. Preliminary experiments with cultured superior cervical ganglion neurons indicate diving-board electrodes can be used with cultured neurons larger than 20 µm in diameter.
In a related technique Helisoma neurons grown on special dish containing a multielectrode array were found to seal to the dish electrodes, establishing similar long-term connections. This capability will make it possible to conduct experiments with either diving-board electrodes or dishes that cannot be performed using conventional techniques.
