Dresden 2006 – scientific programme
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AKB: Biologische Physik
AKB 10: Neuroscience
AKB 10.3: Talk
Tuesday, March 28, 2006, 12:15–12:30, ZEU 255
Electrical field parameters for the electrical stimulation of isolated neurons on wide planar interfaces — •A. Reiher1, H. Witte1, A. Krtschil1, S. Günther1, A. Krost1, A. de Lima2, and T. Voigt2 — 1Inst. of Experimental Physics, University of Magdeburg, PO Box 4120, 39016 Magdeburg — 2Inst. of Physiology, University of Magdeburg, Leipziger Str. 44, 39120 Magdeburg
Embryonal neocortical neurons form physiologically active, synaptically interconnected networks after two weeks in vitro. In order to stimulate larger groups of neurons we developed an interdigitated electrode structure for electrical stimulation of the whole network. This interface consists of a planar finger structure of gold on a 5 nm thin Ti-undercoating with a gap of 300 µm between the electrodes exhibiting an overall electrode thickness of 55 nm. Stimulation conditions leading to synchronous network activity were analyzed in [1]. Here we show that the network activity generated by previous stimulation parameters is not due to the direct activation of single neurons, but depends on widespread synaptic interactions. The parameters for the stimulation of single neurons independent from synaptic interactions were analyzed either by inhibiting glutamate and GABAA receptors in synaptically interconnected networks, or in immature networks with still non-interconnected neurons. The electrical field strength distribution for the interface is calculated with the finite-elements-method. These results are compared with a position dependent analysis of separated firing neurons in order to determine the critical electrical field strength for single neuron stimulation.
[1] A. Reiher, et al., Appl. Phys. Lett. 86, 103901 (2005)