Optical switch and four-wavelength mixing optic developed for the small-animal imager: (left) schematic drawing of the assembly; (right) photograph of device.
Photographs of small-animal imaging platform. (a) Platform with fiber optics (1), strain relief (2), and animal cradle (3); inset shows ear bars with probes (4), curved mouth fiber (5), and dorsal rectilinear optode array (6). (b) Animal fixation and probe placement in the experiment.
(a) Schematic of the adjustable fiber array holder and its position on the animal’s head and (b) cross-sectional schematic of the bent mouth probe.
(a) Long-term stability of the optical signal. Shown for each wavelength are the mean, the minimum, and the maximum CV of the signal variations for all channels during of continuous instrument operation. Error bars indicate standard deviation. (b) Long-term drift of the noise in the optical signal. Shown for each wavelength are the mean, the minimum, the maximum, and the standard deviation (error bars) of temporal fluctuations in signal CV for all channels during of instrument operation.
Four-wavelength calibration results for four measurements performed over : (a) mean source coupling coefficients and (b) mean detector sensitivity coefficients . Error bars indicate extreme values. Viewing from left to right within each group of bars, the data are arranged in the order 726, 760, 810, and .
Geometry used for modeling light transport in the rat head. Positions of the fiber probes are indicated: (a) horizontal (bottom) view and (b) coronal (front) view.
(Color) Results of numerical simulation study: (left) three orthogonal views of geometrical rat head model, with region containing elevated absorption shown in green and (right) corresponding views of recovered image.
Time series of the spatially integrated Hb response to stimulation. Vertical lines indicate start and cessation, for three consecutive epochs of left front paw stimulation.
Spatially integrated hemodynamic response of the rat brain to stimulation. Continuous curves represent the measured response averaged over all trials (error bars indicate standard deviation at each time point). Dashed curves are the analytically derived best-fitting functions that were used as models in the GLM calculations.
(Color) Volume rendering of differential and response, color coded according to the algebraic signs of each pixels’s GLM coefficients.
(Color) Overlay of GLM results onto anatomical cross sections of the rat head for (a) and (b); -dorsal, -ventral, -caudal, -rostral, l-hypothalamus, 2–thalamus, 3–hippocampus, 4–neocortex, 5–muscles (cryosectional images, © UCLA Laboratory of Neuro Imaging, Ref. 31).
(Color) Volume PVA data, obtained from GLM computations.
Cumulative distribution functions of CV values for the image GLM coefficients.
(Color) Volume rendered display of areas having significantly different hemodynamic response to left and right stimulation. Different classes of reaction are color coded.
(Color) Volume rendering of those head areas that show significant differences between PVA values for stimulation of the left and right forepaws.
Volume rendering of those brain regions which react in a significantly different manner to stimulation of left and right forepaws, for both and .
Response strength variation.
GLM coefficient reproducibility.
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