The nucleus of the solitary tract is a potential site for taste-visceral interactions. Connections from the caudal, visceral area of the nucleus (cNST) to the rostral, gustatory zone (rNST) have been described, but the phenotype of cells giving rise to the projection(s) and their distribution among rNST subdivisions are unknown. To determine these characteristics of the intrasolitary pathway, we injected pan-neuronal and floxed AAV viruses into the cNST of mice expressing cre in glutamatergic, GABAergic or catecholaminergic neurons. Particular attention was paid to the terminal field distribution in rNST subdivisions by simultaneously visualizing P2×2 localized to gustatory afferent terminals. All three phenotypically-identified pathways terminated in rNST, with the density greatest for glutamatergic and sparsest for catecholaminergic projections, observations supported by retrograde tracing. Interestingly, cNST neurons had more prominent projections to rNST regions medial and ventral to P2×2 staining, i.e., the medial and ventral subdivisions. In addition, GABAergic neurons projected robustly to the lateral subdivision and adjacent parts of the reticular formation and spinal trigeminal nucleus. Although cNST neurons also projected to the P2×2-rich central subdivision, such projections were sparser. These findings suggest that cNST visceral signals exert stronger excitatory and inhibitory influences on local autonomic and reflex pathways associated with the medial and ventral subdivisions compared to weaker modulation of ascending pathways arising from the central subdivision and ultimately destined for the forebrain.
• Optically-large sprites with upward streamers (carrots and jellyfish) tend to have larger sprite current moments than column sprites • 63 sprites were detected using up to 100,000 fps high-speed video. VLF remote sensing shows that 56% of them have a sprite current signature • Several vigorously luminous sprites have remarkably large peak current moments, up to 2,700 kA km
We present spectra from 400 to 900 nm of a bolt from the blue stepped leader on July 19, 2015 including novel observations from 400 to 600 nm. The spectra of the luminous steps near the tip of the leader look qualitatively similar and contain singly ionized nitrogen lines. The presence of these ionized lines indicate currents and temperatures comparable to peak return stroke. The entire channel illuminates over the final 1.3 ms before attachment, but does not contain evidence of ionization. This neutral spectrum is qualitatively similar to the return stroke spectrum after peak current. This may indicate increasing potential and current along the channel prior to attachment.
This work presents recent measurements of a CH4/H2/N2 turbulent nonpremixed jet flame using an imaging Fourier-transform spectrometer (IFTS). Spatially resolved (128×192 pixels, 0.72 mm/pixel) mean radiance spectra were collected between 1800 cm(-1)≤ν˜≤4500 cm(-1) (2.22 μm≤λ≤5.55 μm) at moderate spectral resolution (δν=16 cm(-1), δλ=20 nm) spanning the visible flame. Higher spectral-resolution measurements (δν=0.25 cm(-1), δλ=0.3 nm) were also captured on a smaller window (8×192) at 20, 40, and 60 diameters above the jet exit and reveal the rotational fine structure associated with various vibrational transitions in CH4, CO2, CO, and H2O. These new imaging measurements compare favorably with existing spectra acquired at select flame locations, demonstrating the capability of IFTS for turbulent combustion studies.
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