Speaker
Description
Unraveling the immense complexity of the human brain requires the ability to selectively interfere and record neural activity. ‘Optogenetics’ describes a variety of techniques for specifically controlling neural activity with light, using light sensitive membrane proteins (opsins).1 Given the significant advantages of nonlinear optics, activating opsins by two-photon absorbance is already an emerging field.2 Activity read-out by means of membrane potential sensing still relies on voltage sensitive fluorescent probes or microelectrode recording. However, it has been proven that retinal analogues can serve as voltage sensing probes by means of second harmonic generation (SHG), when inserted into the cell membrane.3 Since opsins use this retinal chromophore as their photoswitch, we are investigating the potential of opsins to act as voltage reporters. In this contribution we report the molecular first hyperpolarizability characterization of several light sensitive membrane proteins. This parameter is indicative for their potential SHG voltage sensitivity.
Fiala, A., Suska, A. & Schlüter, O. M. Optogenetic approaches in neuroscience. Curr. Biol. 20, R897–903 (2010).
Oron, D., Papagiakoumou, E., Anselmi, F. & Emiliani, V. Two-photon optogenetics. Progress in brain research 196, (Elsevier B.V., 2012).
Theer, P., Denk, W., Sheves, M., Lewis, A. & Detwiler, P. B. Second-harmonic generation imaging of membrane potential with retinal analogues. Biophys. J. 100, 232–42 (2011).
