We report <i>in vivo</i> imaging of neuronal electrical activity from superficial layers of the mouse barrel cortex. The measurements have ∼16-μm spatial and 3-ms temporal resolution and reach depths of 150 μm below the cortical surface. The depth-dependent differential-fluorescence optical sections of activity are consistent with known cortical architecture and represent an important step toward <i>in vivo</i> measurement of functioning complex neural networks. Our observations employ a custom gradient-index lens probe and voltage-sensitive dye fluorescence; the use of epi-illumination rather than dark-field illumination provides the dramatic signal-to-noise improvement necessary for fast three-dimensional imaging.
© 2004 Optical Society of America
(170.1420) Medical optics and biotechnology : Biology
(170.2150) Medical optics and biotechnology : Endoscopic imaging
(170.2520) Medical optics and biotechnology : Fluorescence microscopy
(170.3880) Medical optics and biotechnology : Medical and biological imaging
(170.6900) Medical optics and biotechnology : Three-dimensional microscopy
Jonathan A. N. Fisher, Eugene F. Civillico, Diego Contreras, and Arjun G. Yodh, "In vivo fluorescence microscopy of neuronal activity in three dimensions by use of voltage-sensitive dyes," Opt. Lett. 29, 71-73 (2004)