Submitted on August 16, 2004
Accepted on September 21, 2004
Light-directed electrical stimulation of neurons cultured on silicon wafers
Artem Starovoytov1*, Jung Choi1, and H. Sebastian Seung1
1 Howard Hughes Medical Institute, Chevy Chase, MD, USA
* To whom correspondence should be addressed. E-mail: artems{at}mit.edu.
Dissociated neurons cultured in vitro can serve as a model system for studying the dynamics of neural networks. Such studies depend on techniques for stimulating patterns of neural activity. We demonstrate a new technique for extracellular stimulation of dissociated neurons cultured on silicon wafers. When the silicon surface is reverse biased, electrical current can be generated near any neuron by pulsing a laser. Complex spatiotemporal stimulation patterns can be produced by directing a single beam with an acousto-optic deflector. The technique can generate a stimulating current at any location in the culture. This contrasts with multi-electrode arrays (MEA), which can stimulate only at fixed electrode locations. To characterize reliability and spatial selectivity of stimulation, we used intracellular (patch-clamp)
recordings to monitor the effect of targeted laser pulses on cultured hippocampal neurons. Action potentials could be stimulated with submillisecond precision and 100-micron spatial resolution at rates exceeding 100 Hz. Optimal control parameters for stimulation are discussed.
