We employed a transgenic mouse having conditional expression of ChR2(H134R) in neurons of the inferior olive to facilitate understanding of the role of electrical coupling and oscillation in central nervous system function. Two-photon excitation of ChR2-expressing neurons using 64 laser beams restricted to single inferior olive cell bodies depolarized neurons and evoked voltage deflections in neighboring neurons demonstrating electrical coupling. Broader illumination of neuronal ensembles using blue light induced an optical clamp of endogenous electrical rhythms in the inferior olive of acutely-prepared brain slices, which when applied in vivo directly modulated the local field potential activity and induced tremor. The experiments demonstrate novel methods to optically manipulate electrically coupled potentials and rhythmogenesis within a neuronal ensemble. From a functional perspective, the experiments shed light on the cellular and circuitry mechanisms of essential tremor, a prevalent neurological condition, by indicating time- and frequencydependence of tremor upon varying rhythms of inferior olive stimulation. The experiments indicate analog control of a brain rhythm that may be used to enhance our understanding of the functional consequences of central rhythmogenesis.

Date Published: 8 March 2013
PDF: 9 pages
Proc. SPIE 8586, Optogenetics: Optical Methods for Cellular Control, 85860C (8 March 2013); doi: 10.1117/12.2010204

Published in SPIE Proceedings Vol. 8586:
Optogenetics: Optical Methods for Cellular Control
Samarendra K. Mohanty; Nitish V. Thakor, Editor(s)