title: Brain refractive index measured in vivo with high-NA defocus-corrected full-field OCT and consequences for two-photon microscopy.
abstract: Two-photon laser scanning microscopy (2PLSM) is an important tool for in vivo tissue imaging with sub-cellular resolution, but the penetration depth of current systems is potentially limited by sample-induced optical aberrations. To quantify these, we measured the refractive index n' in the somatosensory cortex of 7 rats in vivo using defocus optimization in full-field optical coherence tomography (ff-OCT). We found n' to be independent of imaging depth or rat age. From these measurements, we calculated that two-photon imaging beyond 200 µm into the cortex is limited by spherical aberration, indicating that adaptive optics will improve imaging depth.
authors: IBENS, UMR 8197 CNRS and INSERM, Ecole Normale Supérieure, 46, Rue d’Ulm, 75005 Paris, France. jonas.binding@espci.fr
authors: Jonas
authors: J
authors: Binding
authors: Juliette
authors: J
authors: Ben Arous
authors: Jean-François
authors: JF
authors: Léger
authors: Sylvain
authors: S
authors: Gigan
authors: Claude
authors: C
authors: Boccara
authors: Laurent
authors: L
authors: Bourdieu
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D001808:Blood Vessels / Q000033:anatomy & histology; D001921:Brain / Q000502:physiology*; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D017785:Photons; D051381:Rats; D017208:Rats, Wistar; D012031:Refractometry; D041623:Tomography, Optical Coherence / Q000379:methods*; D014741:Video Recording