Technical Reports

Using a deep learning approach to track user-defined body parts during various behaviors across multiple species, the authors show that their toolbox, called DeepLabCut, can achieve human accuracy with only a few hundred frames of training data.

The authors introduce a variant GCaMP that is targeted to axons. Due to its strong brightness, signal-to-noise ratio, and photostability, this tool, named axon-GCaMP, enables robust Ca²⁺ imaging in individual axons, including in vivo in awake mice.

The authors present a new approach to create and edit custom spatiotemporal neural activity patterns in awake, behaving animals with extremely high spatial and temporal precision. They present novel opsins optimized for multiphoton optogenetics.

Rabies viral vectors are important tools in neuroscience, but their cytotoxicity usually limits their use. Chatterjee et al. introduce a new class of double-deletion-mutant rabies viral vectors that leaves neurons alive and healthy indefinitely.

This study describes single-nucleus ATAC-seq, a method to profile open chromatin in individual nuclei from frozen tissues. It is used to examine gene regulation in 15,000 nuclei comprising 20 distinct cell types in the developing mouse forebrain.

CRISPR interference-based gene silencing was adopted to achieve highly efficient multiple and conditional gene knockdown in the mouse brain with negligible off-target effects, providing a rapid gene interrogation tool in the mammalian brain.

dCas9-mediated activation has been verified and widely used in vitro. Here the authors generated a potent in vivo activation platform and applied it to control the transcription of multiple genetic elements in the mammalian brain.

The authors present a new computational approach to automatically annotate, analyze, visualize and easily share whole-brain datasets at cellular resolution, based on a scale-invariant and interactive mouse brain reference atlas. The authors applied this framework to define the organization and cocaine-induced activity of corticostriatal circuits.

The authors develop a methods suite for millisecond-precise, single-cell-resolution control of neural activity through protein engineering of novel opsin/trafficking sequence combinations, as well as optimized holographic two-photon optics.

To what extent are population-level results an expected byproduct of simpler structure already known to exist in single neurons? Conventional controls are insufficient to perform this critical investigation. The authors developed a methodological framework to test the significance of population-level studies and apply it to prefrontal and motor cortices.

The authors report two new engineered AAV capsids that efficiently deliver genes throughout the adult central and peripheral nervous systems after intravenous administration. Complementing these capsids is an AAV toolbox that enables cell morphology and genetic manipulation studies of defined neural cell types in transgenic or wild-type animals.

The authors demonstrate that optical fibers with tapered tips can homogenously illuminate either elongated brain structures or dynamically selected subregions. Tapered fibers achieve efficient optogenetic stimulation in vivo with minimal tissue damage. In addition, a single fiber can deliver light of multiple wavelengths to independently controlled regions.

No techniques exist for the precise identification of vascular pericytes. Here the authors identify and characterize a fluorescent dye that exclusively labels pericytes. Using this tool for intravital imaging of the mouse brain, the authors provide conclusive evidence that these cells are molecularly and functionally distinct from all other brain and vascular cells.

Pandya et al. describe a protocol to differentiate human and mouse iPSCs into cells with the phenotype, transcriptional profile and functional properties of microglia. The treatment of murine intracranial malignant gliomas with these cells demonstrates their potential clinical use. These microglia-like cells will enable further studies into the role of microglia in health and disease.

The authors built a simple optical module that generates axially extended Bessel foci, optimized for in vivo brain imaging. Easily incorporated into existing two-photon fluorescence microscopes, this module allowed 30-Hz volumetric functional imaging of sparsely labeled brains at synaptic resolution in a variety of model organisms in vivo.

The authors use fiber-based fabrication to create flexible biocompatible probes with integrated optical, electrical and microfluidic capabilities. Functionality is demonstrated by characterizing the temporal dynamics of opsin expression following viral delivery, long-term tracking of individual neuron action potentials and modulation of neural circuits in the context of mouse behavior.

The ability to target and manipulate specific neuronal populations is crucial for understanding brain function. In this report, the authors describe a novel virus that restricts gene expression to telencephalic GABAergic interneurons, allowing for morphological visualization, activity monitoring and functional manipulation of interneurons in mice and in non-genetically tractable species.

Silicon microelectrodes are a powerful technique for recording neuronal population activity. Increases in probe size and density make for larger recordable populations, but also require new techniques for processing the resulting data. The authors describe a suite of practical, open source software for spike sorting of large, dense electrode arrays.

Elucidation of structure–function relationships in the nervous system necessitates biological circuit control with genetic and temporal precision. Here the authors engineer a genetically encoded magnetically sensitive actuator, “Magneto,” and remotely manipulate behavior in live zebrafish and mice. The magnetogenetic control over neural activity promises greater access to previously intractable tissues.

Recurrent, reciprocal genomic disorders due to non-allelic homologous recombination (NAHR) are a major cause of human disease. The authors developed a CRISPR/Cas9 genome engineering method that directly targets segmental duplications and efficiently mimics the NAHR-mediated mechanism of microdeletion and microduplication that occurs in vivo using 16p11.2 and 15q13.3 as proof-of-principle models.