title: In vivo imaging of cerebral energy metabolism with two-photon fluorescence lifetime microscopy of NADH.
abstract: Minimally invasive, specific measurement of cellular energy metabolism is crucial for understanding cerebral pathophysiology. Here, we present high-resolution, in vivo observations of autofluorescence lifetime as a biomarker of cerebral energy metabolism in exposed rat cortices. We describe a customized two-photon imaging system with time correlated single photon counting detection and specialized software for modeling multiple-component fits of fluorescence decay and monitoring their transient behaviors. In vivo cerebral NADH fluorescence suggests the presence of four distinct components, which respond differently to brief periods of anoxia and likely indicate different enzymatic formulations. Individual components show potential as indicators of specific molecular pathways involved in oxidative metabolism.
authors: Optics Division, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129,  USA.
authors: Mohammad A
authors: MA
authors: Yaseen
authors: Sava
authors: S
authors: Sakadžić
authors: Weicheng
authors: W
authors: Wu
authors: Wolfgang
authors: W
authors: Becker
authors: Karl A
authors: KA
authors: Kasischke
authors: David A
authors: DA
authors: Boas
keywords: (170.0170) Medical optics and biotechnology; (170.3650) Lifetime-based sensing; (180.4315) Nonlinear microscopy