Cortical slices allow for simultaneous imaging of multiple cortical layers. However, slices lack native physiological inputs and outputs. Although in vivo, two-photon imaging preserves the native context, it is typically limited to a depth of <500 microm. In addition, simultaneous imaging of multiple cortical layers is difficult due to the stratified organization of the cortex. We demonstrate the use of 1-mm microprisms for in vivo, two-photon neocortical imaging. These prisms enable simultaneous imaging of multiple cortical layers, including layer V, at an angle typical of slice preparations. Images were collected from the mouse motor and somatosensory cortex and show a nearly 900-microm-wide field of view. At high-magnification imaging using an objective with 1-mm of coverglass correction, resolution is sufficient to resolve dendritic spines on layer V neurons. Images collected using the microprism are comparable to images collected from a traditional slice preparation. Functional imaging of blood flow at various neocortical depths is also presented, allowing for quantification of red blood cell flux and velocity. H&E staining shows the surrounding tissue remains in its native, stratified organization. Estimation of neuronal damage using propidium iodide and a fluorescent Nissl stain reveals cell damage is limited to <100 microm from the tissue-glass interface. Microprisms are a straightforward tool offering numerous advantages for into neocortical tissue.

History of concomitant intraocular surgery with GDD implantation may be a potential risk factor for future erosions.

Two-photon fluorescence lifetime imaging (FLIM) of molecules can reveal important information on the local microenvironment. NADH, an intrinsic fluorescent molecule and ubiquitous metabolic co-enzyme, has a lifetime that depends strongly on enzymatic binding. We present a custom image-processing algorithm for raw fluorescence lifetime and amplitude data that produces an image showing spatially distinct NADH fluorescence lifetimes in slices of rat and human brain. NADH FLIM images were collected in control and epileptic rat tissue. Differences in spatial patterns of NADH lifetimes support the hypothesis that NADH binding, and thus metabolic capacity, is significantly different between groups. This type of analysis can provide information on metabolic states in pathological material.

Typical imaging depths with multiphoton microscopy (MPM) are limited to less than 300 mum in many tissues due to light scattering. Optical clearing significantly reduces light scattering by replacing water in the organ tissue with a fluid having a similar index of refraction to that of proteins. We demonstrate MPM of intact, fixed, cleared mouse organs with penetration depths and fields of view in excess of 2 mm. MPM enables the creation of large 3-D data sets with flexibility in pixel format and ready access to intrinsic fluorescence and second-harmonic generation. We present high-resolution images and 3-D image stacks of the brain, small intestine, large intestine, kidney, lung, and testicle with image sizes as large as 4,096 x 4,096 pixels.

Genuine U.S. Federal Reserve Notes have a consistent, two-component intrinsic fluorescence lifetime. This allows for detection of counterfeit paper money because of its significant differences in fluorescence lifetime when compared to genuine paper money. We used scanning two-photon laser excitation and the time-correlated single photon counting (TCSPC) method to sample a approximately 4 mm(2) region. Three types of counterfeit samples were tested. Four out of the nine counterfeit samples fit to a one-component decay. Five out of nine counterfeit samples fit to a two-component model, but are identified as counterfeit due to significant deviations in the longer lifetime component compared to genuine bills.