The mesoSPIM initiative: open-source light-sheet microscopes for imaging cleared tissue.

Light-sheet microscopy is an ideal technique for imaging large cleared samples; however, the community is still lacking instruments capable of producing volumetric images of centimeter-sized cleared samples with near-isotropic resolution within minutes. Here, we introduce the mesoscale selective plane-illumination microscopy initiative, an open-hardware project for building and operating a light-sheet microscope that addresses these challenges and is compatible with any type of cleared or expanded sample ( www.mesospim.

Adeno-associated Virus-mediated Transgene Expression in Genetically Defined Neurons of the Spinal Cord.

Selective manipulation of spinal neuronal subpopulations has mainly been achieved by two different methods: 1) Intersectional genetics, whereby double or triple transgenic mice are generated in order to achieve selective expression of a reporter or effector gene (e.g., from the Rosa26 locus) in the desired spinal population.

Spinal nociceptive circuit analysis with recombinant adeno-associated viruses: the impact of serotypes and promoters.

Recombinant adeno-associated virus (rAAV) vector-mediated gene transfer into genetically defined neuron subtypes has become a powerful tool to study the neuroanatomy of neuronal circuits in the brain and to unravel their functions. More recently, this methodology has also become popular for the analysis of spinal cord circuits. To date, a variety of naturally occurring AAV serotypes and genetically modified capsid variants are available but transduction efficiency in spinal neurons, target selectivity, and the ability for retrograde tracing are only incompletely characterized.

Targeted ablation, silencing, and activation establish glycinergic dorsal horn neurons as key components of a spinal gate for pain and itch.

The gate control theory of pain proposes that inhibitory neurons of the spinal dorsal horn exert critical control over the relay of nociceptive signals to higher brain areas. Here we investigated how the glycinergic subpopulation of these neurons contributes to modality-specific pain and itch processing. We generated a GlyT2::Cre transgenic mouse line suitable for virus-mediated retrograde tracing studies and for spatially precise ablation, silencing, and activation of glycinergic neurons.

Morphological, biophysical and synaptic properties of glutamatergic neurons of the mouse spinal dorsal horn.

Interneurons of the spinal dorsal horn are central to somatosensory and nociceptive processing. A mechanistic understanding of their function depends on profound knowledge of their intrinsic properties and their integration into dorsal horn circuits. Here, we have used BAC transgenic mice expressing enhanced green fluorescent protein (eGFP) under the control of the vesicular glutamate transporter (vGluT2) gene (vGluT2::eGFP mice) to perform a detailed electrophysiological and morphological characterisation of excitatory dorsal horn neurons, and to compare their properties to those of GABAergic (Gad67::eGFP tagged) and glycinergic (GlyT2::eGFP tagged) neurons.