Abstract:Transgenic methods enable the selective manipulation of neurons for functional mapping of neuronal circuits. Using confocal microscopy, we have imaged the cellular-level expression of 109 transgenic lines in live 6 day post fertilization larvae, including 80 Gal4 enhancer trap lines, 9 Cre enhancer trap lines and 20 transgenic lines that express fluorescent proteins in defined gene-specific patterns. Image stacks were acquired at single micron resolution, together with a broadly expressed neural marker, which … Show more
“…Co-expression of nuclear-localized DsRed2 enabled accurate automated segmentation of neurons and extraction of neuronal activity traces (Figure 1D,E; Figure S1B,C). We registered the position of each active neuron to a common reference brain [12], allowing us to compare the responsiveness of 34,050 spatially located Gsx1 neurons on each trial type (Figure 1F). …”
Filtering mechanisms prevent a continuous stream of sensory information from swamping perception, leading to diminished focal attention and cognitive processing. Mechanisms for sensory gating are commonly studied using prepulse inhibition, a paradigm that measures the regulated transmission of auditory information to the startle circuit; however, the underlying neuronal pathways are unresolved. Using large-scale calcium imaging, optogenetics, and laser ablations, we reveal a cluster of 30 morphologically identified neurons in zebrafish that suppress the transmission of auditory signals during prepulse inhibition. These neurons project to a key sensorimotor interface in the startle circuit-the termination zone of auditory afferents on the dendrite of a startle command neuron. Direct measurement of auditory nerve neurotransmitter release revealed selective presynaptic inhibition of sensory transmission to the startle circuit, sparing signaling to other brain regions. Our results provide the first cellular resolution circuit for prepulse inhibition in a vertebrate, revealing a central role for presynaptic gating of sensory information to a brainstem motor circuit.
“…Co-expression of nuclear-localized DsRed2 enabled accurate automated segmentation of neurons and extraction of neuronal activity traces (Figure 1D,E; Figure S1B,C). We registered the position of each active neuron to a common reference brain [12], allowing us to compare the responsiveness of 34,050 spatially located Gsx1 neurons on each trial type (Figure 1F). …”
Filtering mechanisms prevent a continuous stream of sensory information from swamping perception, leading to diminished focal attention and cognitive processing. Mechanisms for sensory gating are commonly studied using prepulse inhibition, a paradigm that measures the regulated transmission of auditory information to the startle circuit; however, the underlying neuronal pathways are unresolved. Using large-scale calcium imaging, optogenetics, and laser ablations, we reveal a cluster of 30 morphologically identified neurons in zebrafish that suppress the transmission of auditory signals during prepulse inhibition. These neurons project to a key sensorimotor interface in the startle circuit-the termination zone of auditory afferents on the dendrite of a startle command neuron. Direct measurement of auditory nerve neurotransmitter release revealed selective presynaptic inhibition of sensory transmission to the startle circuit, sparing signaling to other brain regions. Our results provide the first cellular resolution circuit for prepulse inhibition in a vertebrate, revealing a central role for presynaptic gating of sensory information to a brainstem motor circuit.
“…Rostral is to the left in all images. Scale bars: 100 µm ( b, s, t ), 50 μm ( c, h–n ), 200 µm ( f,g , o–q ). DOI:
http://dx.doi.org/10.7554/eLife.24369.00710.7554/eLife.24369.008Figure 4—figure supplement 1.Radial Glia and FGPs localize to different parts of the brain.( a ) Dorsal view of a Z-projected confocal image generated by the Zebrafish Brain Browser (Marquart et al, 2015) superimposing four 6 dpf Tg(lyve1:dsRed) (green) embryos to Tg(gfap:GFP ) (magenta). Rostral is to the left.…”
The blood-brain barrier is essential for the proper homeostasis and function of the CNS, but its mechanism of function is poorly understood. Perivascular cells surrounding brain blood vessels are thought to be important for blood-brain barrier establishment, but their roles are not well defined. Here, we describe a novel perivascular cell population closely associated with blood vessels on the zebrafish brain. Based on similarities in their morphology, location, and scavenger behavior, these cells appear to be the zebrafish equivalent of cells variably characterized as Fluorescent Granular Perithelial cells (FGPs), perivascular macrophages, or ‘Mato Cells’ in mammals. Despite their macrophage-like morphology and perivascular location, zebrafish FGPs appear molecularly most similar to lymphatic endothelium, and our imaging studies suggest that these cells emerge by differentiation from endothelium of the optic choroidal vascular plexus. Our findings provide the first report of a perivascular cell population in the brain derived from vascular endothelium.DOI:
http://dx.doi.org/10.7554/eLife.24369.001
“…These structures primarily consisted of region boundaries, known clusters of neurons, midline points, ganglia, and the brain outline. The same Z-Brain landmarks were used for transforming a version 51 of the Zebrafish Brain Browser 52 that was previously registered into the Z-Brain atlas.…”
High-resolution serial-section electron microscopy (ssEM) makes it possible to investigate the dense meshwork of axons, dendrites, and synapses that form neuronal circuits(1). However, the imaging scale required to comprehensively reconstruct these structures is more than ten orders of magnitude smaller than the spatial extents occupied by networks of interconnected neurons(2), some of which span nearly the entire brain. Difficulties in generating and handling data for large volumes at nanoscale resolution have thus restricted vertebrate studies to fragments of circuits. These efforts were recently transformed by advances in computing, sample handling, and imaging techniques(1), but high-resolution examination of entire brains remains a challenge. Here, we present ssEM data for the complete brain of a larval zebrafish (Danio rerio) at 5.5 days post-fertilization. Our approach utilizes multiple rounds of targeted imaging at different scales to reduce acquisition time and data management requirements. The resulting dataset can be analysed to reconstruct neuronal processes, permitting us to survey all myelinated axons (the projectome). These reconstructions enable precise investigations of neuronal morphology, which reveal remarkable bilateral symmetry in myelinated reticulospinal and lateral line afferent axons. We further set the stage for whole-brain structure-function comparisons by co-registering functional reference atlases and in vivo two-photon fluorescence microscopy data from the same specimen. All obtained images and reconstructions are provided as an open-access resource
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