Functional patterned multiphoton excitation deep inside scattering tissue

Eirini Papagiakoumou (1) , Aurélien Bègue (2) , Ben Leshem , Osip Schwartz , Brandon Stell (3) , Jonathan Bradley (3) , Dan Oron (4) , Valentina Emiliani (1)

1 UMR 8250 - Laboratoire de Neurophotonique
2 NNM (UM 82) - Neurophysiologie et nouvelles microscopies
3 LPC - UMR 8118 - Laboratoire de physiologie cérébrale
4 Department of Physics of Complex Systems

Stochastic distortion of light beams in scattering samples makes in-depth photoexcitation in brain tissue a major challenge. A common solution for overcoming scattering involves adaptive pre-compensation of the unknown distortion1,2,3. However, this requires long iterative searches for sample-specific optimized corrections, which is a problem when applied to optical neurostimulation where typical timescales in the system are in the millisecond range. Thus, photoexcitation in scattering media that is independent of the properties of a specific sample would be an ideal solution. Here, we show that temporally focused two-photon excitation4 with generalized phase contrast5 enables photoexcitation of arbitrary spatial patterns within turbid tissues with remarkable robustness to scattering. We demonstrate three-dimensional confinement of tailored photoexcitation patterns >200 µm in depth, both in numerical simulations and through brain slices combined with patch-clamp recording of photoactivated channelrhodopsin-2.

Domaines: Optique [physics.optics]; Neurobiologie

Eirini Papagiakoumou, Aurélien Bègue, Ben Leshem, Osip Schwartz, Brandon Stell, et al.. Functional patterned multiphoton excitation deep inside scattering tissue. Nature Photonics, 2013, 7 (4), pp.274-278. ⟨10.1038/NPHOTON.2013.9⟩. ⟨hal-02444281⟩