@article {69338,
	title = {Innexin expression in electrically coupled motor circuits},
	journal = {Neuroscience Letters},
	volume = {695},
	year = {2019},
	month = {2019 Mar 16},
	pages = {19-24},
	abstract = {<p>The many roles of innexins, the molecules that form gap junctions in invertebrates, have been explored in numerous species. Here, we present a summary of innexin expression and function in two small, central pattern generating circuits found in crustaceans: the stomatogastric ganglion and the cardiac ganglion. The two ganglia express multiple innexin genes, exhibit varying combinations of symmetrical and rectifying gap junctions, as well as gap junctions within and across different cell types. Past studies have revealed correlations in ion channel and innexin expression in coupled neurons, as well as intriguing functional relationships between ion channel conductances and electrical coupling. Together, these studies suggest a putative role for innexins in correlating activity between coupled neurons at the levels of gene expression and physiological activity during development and in the adult animal.</p>
},
	keywords = {Cardiac ganglion, Central pattern generators, Crustacean, Neuronal homeostasis, Stomatogastric ganglion},
	issn = {0304-3940},
	doi = {https://doi.org/10.1016/j.neulet.2017.07.016},
	url = {https://www.sciencedirect.com/science/article/pii/S0304394017305785},
	author = {Adriane G. Otopalik and Brian Lane and David J. Schulz and Eve Marder}
}
@article {69337,
	title = {Molecular Profiling to Infer Neuronal Cell Identity: Lessons from small ganglia of the Crab Cancer borealis},
	journal = {bioRxiv},
	year = {2019},
	month = {2019 Jul 2},
	abstract = {<p>Understanding circuit organization depends on identification of cell types. Recent advances in transcriptional profiling methods have enabled classification of cell types by their gene expression. While exceptionally powerful and high throughput, the ground-truth validation of these methods is difficult: if cell type is unknown, how does one assess whether a given analysis accurately captures neuronal identity? To shed light on the capabilities and limitations of solely using transcriptional profiling for cell type classification, we performed two forms of transcriptional profiling {\textendash} RNA-seq and quantitative RT-PCR, in single, unambiguously identified neurons from two small crustacean networks: the stomatogastric and cardiac ganglia. We then combined our knowledge of cell type with unbiased clustering analyses and supervised machine learning to determine how accurately functionally-defined neuron types can be classified by expression profile alone. Our results demonstrate that expression profile is able to capture neuronal identity most accurately when combined with multimodal information that allows for post-hoc grouping so analysis can proceed from a supervised perspective. Solely unsupervised clustering can lead to misidentification and an inability to distinguish between two or more cell types. Therefore, our study supports the general utility of cell identification by transcriptional profiling, but adds a caution: it is difficult or impossible to know under what conditions transcriptional profiling alone is capable of assigning cell identity. Only by combining multiple modalities of information such as physiology, morphology or innervation target can neuronal identity be unambiguously determined.SIGNIFICANCE STATEMENT Single cell transcriptional profiling has become a widespread tool in cell identification, particularly in the nervous system, based on the notion that genomic information determines cell identity. However, many cell type classification studies are unconstrained by other cellular attributes (e.g., morphology, physiology). Here, we systematically test how accurately transcriptional profiling can assign cell identity to well-studied anatomically- and functionally-identified neurons in two small neuronal networks. While these neurons clearly possess distinct patterns of gene expression across cell types, their expression profiles are not sufficient to unambiguously confirm their identity. We suggest that true cell identity can only be determined by combining gene expression data with other cellular attributes such as innervation pattern, morphology, or physiology.</p>
},
	doi = {10.1101/690388},
	url = {https://www.biorxiv.org/content/early/2019/07/02/690388},
	author = {Adam J. Northcutt and Daniel R. Kick and Adriane G. Otopalik and Benjamin M. Goetz and Rayna M. Harris and Joseph M. Santin and Hans A. Hofmann and Eve Marder and David J. Schulz}
}
