Fig. 5.

Rat brain choroid plexus. A 243 μm × 243 μm × 44 μm image volume is shown from a large intact rostral half of the brain. (a) En face (x − y) phase contrast image produced by original OBM, cross section at 15 μm depth. Bottom shows x − z cross section. Scale bar represents 50 μm. Left inset, axial (k_x, k_z) Fourier space of reconstructed volume. Right inset, transverse (k_x, k_y) Fourier space of reconstructed volume. Spatial frequency axes shown span ± 3.7 μm⁻¹ laterally (k_x, k_y) and ± 1 μm⁻¹ axially (k_z). Note missing bow-tie region due to lack of transverse shear information. (b) Same regionas (a), 2D reconstruction from two orthogonal illuminations. Left and right insets, corresponding Fourier space cross sections in x − z and x − y spatial frequencies, respectively. Note cylindrical shape of reconstructed support structure, indicating a passage of high z-frequency noise. (c) Same region as (b), but with a 3D OTF reconstruction. Note the preservation of low- to mid-range frequencies indicating mesoscale structure of epithelial folds in choroid plexus. Left and right insets, corresponding Fourier space cross sections in x − z and x − y spatial frequencies, respectively. Note that the region of support is roughly limited to frequencies predicted by the 3D linear OTF.