Comparison of two <i>in vivo</i> methods for astrocytes staining (P21 rat).

<p>TPLSM images acquired: <b>A_1–3</b>) 30 minutes after SRB (20 mg/kg) intravenous injection and <b>B_1–3</b>) 5 minutes after SR101 application (100 µM) on the cortical surface. (<b>A₁</b>) and (<b>B₁</b>) Images were taken at 100 µm below the pia.mater (<b>A₂</b>) and (<b>B₂</b>) Images were taken at 250 µm below the surface of the cortex. (<b>A₃</b>) and (<b>B₃</b>) show a 3D reconstruction (V3D) using the entire stack of images. Scale bar = 50 µm.</p

Rearrangement of the astroglial network in a mouse model of mesiotemporal lobe epilepsy.

<p><b>A–B</b>) Bright field microscopy imaging (Nikon Multizoom AZ100, France) of acute hippocampal slices from adult mice 2 weeks after a unilateral intrahippocampal kainate injection. <b>A</b>) Contralateral non-injected hippocampus. <b>B</b>) Ipsilateral hippocampus. Note the absence of CA1/CA3 areas and the enlargement of the dentate gyrus. <b>C–D</b>) TPLSM imaging of regions indicated by white squares on (A) and (B) images, respectively, after iv injection of SR101. Scale bar = 50 µm. <b>E</b>) Column scatters representation showing the distribution of astrocytes cell body volumes at both sides of the hippocampus. The bar corresponds to the mean value.</p

Calcium signaling in neocortical astrocytes stained with SR101.

<p><b>A</b>) Left panel: merged confocal images of astrocytes labeled with SR101 (iv injection; red) and incubated with 5 µM Fluo-4 AM (green) in acute brain slice (P17 rat). Right panel: example of typical fluorescence variations measured in three SR101-stained astrocytes within the somatosensory cortex. <b>B</b>) Left panel: merged confocal imaging of astrocytes stained with both SR101 (red) and Fluo-4 AM (green). Right panel: example of fluorescence increase induced by ATP (5 µM) measured in three typical SR101 positive cells. <b>C</b>) Left panel: confocal imaging of astrocytes loaded with Fluo-4 AM (green). Right panel: example of fluorescence increase induced by ATP (5 µM) measured in three loaded astrocytes. <b>D</b>) Left panel: TPLSM imaging of cortical astrocytes <i>in vivo</i> 1 hour after an iv injection of SR101 (P18 rat, depth = 200 µm). Right panel: example of fluorescence variations measured in two SR101-stained astrocytes within the somatosensory cortex layer 2/3 labeled with Fluo-4 AM. Scale bar = 50 µm.</p

3D morphological analysis of the astrocytic network after iv injection of SRB.

<p><b>A</b>) A multistacks mosaic acquired in the somatosensory area of a coronal acute brain slice (P17 rat). The region of interest (ROI; white rectangle) shows colored astrocytes detected using ImageJ plugins. Each color corresponds to single astrocytes cell body. Scale bar = 150 µm. <b>B</b>) Frequency histogram showing of astrocyte densities as a function of cortical depth calculated from the ROI described above. Depth was divided in 15 bins with 100 µm increments. <b>C</b>) Frequency histogram of normalized astrocytes radial densities in the cortical layer 1 and <b>E</b>) in layers 2/3. <b>D</b>) TPLSM images showing astrocytes in the cortical layer 1 and <b>F</b>) in layers 2/3. Scale bar = 25 µm.</p

Sulforhodamine stained cells are only astrocytes.

<p><b>A</b>) Two-photon excitation spectra of SRB and SR101 shows the possibility to excite one dye without exciting the other. Z-projection (standard-deviation) of a 100 µm stack acquired on an acute coronal brain slice of rat somatosensory cortex (P23) after iv injection of SRB/SR101 mix (1∶1) and FITC-dextran to stain vasculature. The left merged image was acquired with an 800 nm laser excitation wavelength, corresponding to SRB (orange) and FITC-dextran (green) emissions. The central merged image was acquired with a 900 nm laser excitation wavelength, corresponding to SR101 (red) and FITC-dextran (green) emissions. The right panel shows a merge of SRB, SR101 and FITC-dextran (pink corresponds to SRB and SR101 colocalization). Scale bar = 50 µm. <b>B</b>) Z-projection (standard-deviation) of two-photon microscopy images of cortical brain slices from GFAP-GFP transgenic mouse (P37) 2 h after iv injection of SRB. Left image shows SRB staining (red), central image shows GFAP-GFP expression (green) and right panel is a merge of left and central images with double-stained cells appearing in yellow. <b>C</b>) Z-projection (standard-deviation) of TPLSM images of cortical brain slices from a P18 rat. Left image: SRB astrocytes staining after iv injection (red), central image: slice immunostained with S100B antibody (green). Right panel is a merge of left and central images with double-stained cells appearing in yellow. <b>D</b>) Merge images of SRB-stained slices (red) secondarily immunostained with NG2 antibody (green, left panel), or NeuN antibody (green, central panel), or CD11b antibody (green, right panel). Arrowheads show NG2 cells or microglial cells which are not SRB-stained. Scale bar = 20 µm.</p

Comparison of two methods for astrocytes staining in acute brain slices (thickness of 300 µm, P18 rat).

<p>TPLSM images: <b>A–D</b>) brain slicing performed 2 h after intravenous injection of SR101 (20 mg/kg) and <b>E–F</b>) brain slices incubated 15 minutes with SR101 (final concentration 1 µM) in aCSF. Z-projections (standard-deviations) of acquired stacks: <b>A</b>) in the cortical L1 and L2/3 (stack thickness 300 µm); <b>B</b>) in the dentate gyrus (stack thickness 150 µm); <b>C</b>) in the substantia nigra pars reticulata (stack thickness 100 µm) and <b>D</b>) in the cerebellum (stack thickness 50 µm). Images collected after incubation with SR101: <b>E</b>) at the surface of the slice, and <b>F</b>) 80 µm deeper from the brain slice surface. Scale bar = 50 µm.</p

Linking Small-scale Solar Wind Properties with Large-scale Coronal Source Regions through Joint Parker Solar Probe-Metis/Solar Orbiter Observations

The solar wind measured in situ by Parker Solar Probe in the very inner heliosphere is studied in combination with the remote-sensing observation of the coronal source region provided by the METIS coronagraph aboard Solar Orbiter. The coronal outflows observed near the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and 6.3 R ⊙ above the eastern solar limb, can be associated with the streams sampled by PSP at 0.11 and 0.26 au from the Sun, in two time intervals almost 5 days apart. The two plasma flows come from two distinct source regions, characterized by different magnetic field polarity and intensity at the coronal base. It follows that both the global and local properties of the two streams are different. Specifically, the solar wind emanating from the stronger magnetic field region has a lower bulk flux density, as expected, and is in a state of well-developed Alfvénic turbulence, with low intermittency. This is interpreted in terms of slab turbulence in the context of nearly incompressible magnetohydrodynamics. Conversely, the highly intermittent and poorly developed turbulent behavior of the solar wind from the weaker magnetic field region is presumably due to large magnetic deflections most likely attributed to the presence of switchbacks of interchange reconnection origin.</p