Selective stimulation of a target neuron in micropatterned neuronal circuits using a pair of needle electrodes

Neurostimulation is an essential technique to trigger and modulate the spatiotemporal activity of local neuronal circuits. Current stimulation methods have a trade-off relationship among aiming precision, temporal resolution, and noninvasiveness, making it difficult to stimulate and monitor a single target neuron for a long term. Here, we show that a method using two needle electrodes in combination of micropatterning techniques provides new possibilities for targeting and stimulating a single neuron selectively. Results of physiological experiments as well as analog circuit simulation reveal that two needle electrodes can stimulate a target neuron selectively by placing the two needle electrodes in proximity to and to straddle the target neuron, and that the steepness of voltage applied to two needle electrodes is important for the target neuron to fire at a low voltage. The proposed method enables a noninvasive stimulation suitable for measuring long-term activity of local neuronal circuits.