Fig. 1
From: Neuroinflammation increases oxygen extraction in a mouse model of Alzheimer’s disease
Experimental design and data acquisition. (A) Imaging set up for 2P-PLIM measurement in head-fixed, awake mice. 80 MHz, ultrafast pulsed laser tuned to 950 nm. The excitation laser is reflected by a 700 nm short pass filter and a 900 nm dichroic filter and is focused to the imaging field through a 25X heated, water-immersive objective. The emission light is reflected and transmitted through the dichroic and the 640 long-pass emission filter, and then detected by a photon-counting PMT. (B) Wide-field imaging of an AD mouse cranial window in the left somatosensory cortex. The red box indicates the region (Field of View: 474.27 × 474.27 µm2) being measured by two-photon microscopy. A: anterior, P: posterior, M: medial, L: lateral. C Two-photon survey scan image of the red-boxed field of view in B at cortical depth z = 200 μm, scale bar = 100 μm. Colored dots are points of measurement of intravascular pO2 and RBC flux, color-coded by pO2 values. D Time-resolved phosphorescence decays of the corresponding pixels in C. Decays are color-coded by pO2 values. E Time-integrated phosphorescence intensity within a single capillary measurement over 600 ms (corresponding to 2000 PLIM measurements). Black curve is the time-integrated photon total counts. Local minima correspond to single, non-labelled erythrocytes traversing through the capillary (black). The black photon count trace was thresholded (red) to count the number of RBCs (valleys of the intensity curve) over time. F Experimental timeline. EOM: electro-optic modulator. SH: shutter. M: mirror. GM: galvanometer scanner. SL: scan lens. TL: tube lens. SP: short-pass filter. LP: long-pass filter. DM: dichroic mirror. PMT: GaAsP photomultiplier tube