About this Research Topic
The nervous system is composed of diverse neuronal and nonneuronal cell types with different molecular, anatomical, and functional features. These heterogenous populations of cells arise during development and assemble to form functional circuits under the instruction of genetic programs with influences from the environment. The complex yet flexible functions of the nervous system rely on the cooperation of multiple cell types that are functionally specialized. Cataloguing, characterizing, and assessing cell types are essential for understanding the genetic principle of neural development and the organizational rules of neural circuits.
More than two centuries ago, Santiago Ramòn y Cajal had already uncovered the great morphological diversity of cells in the nervous system using Golgi staining. Since then, our understanding about cell type diversity has expanded and extended to include many different aspects, ranging from molecular signatures and anatomical features, to developmental history and circuit function. Recent developments in single cell sequencing and single neuron anatomy further reveal the daunting molecular and morphological diversity of cells. Combined with genetic targeting strategies, our knowledge about the connectivity and function of distinct cell types has greatly advanced through virus-mediated circuit mapping, as well as optogenetic, chemogenetic, imaging, and electrophysiological-based activity probing techniques applied in behaving animals. Novel approaches in lineage tracing based on genome engineering, sparse labeling, multiplex fluorescent and barcode tagging accelerated our understanding of neural development. With the rapid accumulation of big data from high throughput sequencing, high resolution imaging, and multi-electrode recordings, data mining has also become a routine yet challenging part of cell type-specific studies in modern neuroscience.
However, we are still far from a full characterization of all features relevant to any single cell type, or a complete description of any single feature of all cell types in the nervous system of any species. There is not yet a set of well-agreed rules to unambiguously catalogue all cell types in the nervous system, especially for mammals. Other than C.elegans and Drosophila, there is also a big gap between the urgent needs to assess cell types and the availability of cell type-specific tools in most model organisms with more complex nervous systems. The development of integrative multi-modal approaches will be essential for both accurately defining and experimentally assessing distinct cell types.
The goal of this Research Topic is to introduce novel findings and technological advances that: i) improve the classification, characterization, targeting, and manipulation of different cell types in the nervous system, and ii) investigate the development and function of specific cell types in neural circuits. We also welcome reviews that summarize current knowledge, recent advances, and perspectives on problems and challenges for future research.
Themes of interest include but are not limited to the following:
• The acquisition and maintenance of cell-type specific features during development, such as molecular signatures (transcriptome, epigenome, proteome, metabolome), anatomy (lineage, location, size, orientation, morphology, connectivity) and functional specialization
• The strategies and tools to characterize and classify cell types based on single or multi-modal cell features, to access specific cell types for molecular, anatomical and functional analysis, or to follow developmental history and dissect lineage relationships of diverse cell types in the nervous system
• The functional roles played by diverse cell types in neural circuits, and their contribution to behaviors
Keywords: Celluar taxonomy, cell lineage, genetic targeting, development, circuit function
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.