@article {68593, title = {Desmosomal connectomics of all somatic muscles in an annelid larva.}, journal = {eLife}, volume = {11}, year = {2022}, month = {2022 Dec 20}, abstract = {

Cells form networks in animal tissues through synaptic, chemical, and adhesive links. Invertebrate muscle cells often connect to other cells through desmosomes, adhesive junctions anchored by intermediate filaments. To study desmosomal networks, we skeletonised 853 muscle cells and their desmosomal partners in volume electron microscopy data covering an entire larva of the annelid . Muscle cells adhere to each other, to epithelial, glial, ciliated, and bristle-producing cells and to the basal lamina, forming a desmosomal connectome of over 2000 cells. The aciculae - chitin rods that form an endoskeleton in the segmental appendages - are highly connected hubs in this network. This agrees with the many degrees of freedom of their movement, as revealed by video microscopy. Mapping motoneuron synapses to the desmosomal connectome allowed us to infer the extent of tissue influenced by motoneurons. Our work shows how cellular-level maps of synaptic and adherent force networks can elucidate body mechanics.

}, keywords = {Animals, Annelida, Connectome, Larva, Muscles, Polychaeta}, issn = {2050-084X}, doi = {10.7554/eLife.71231}, author = {Jasek, Sanja and Veraszt{\'o}, Csaba and Brodrick, Emelie and Shahidi, R{\'e}za and Kazimiers, Tom and Kerbl, Alexandra and J{\'e}kely, G{\'a}sp{\'a}r} } @article {68222, title = {Structured sampling of olfactory input by the fly mushroom body.}, journal = {Current Biology}, volume = {32}, year = {2022}, month = {2022 Aug 08}, pages = {3334-3349.e6}, abstract = {

Associative memory formation and recall in the fruit fly Drosophila melanogaster is subserved by the mushroom body (MB). Upon arrival in the MB, sensory information undergoes a profound transformation from broadly tuned and stereotyped odorant responses in the olfactory projection neuron (PN) layer to narrowly tuned and nonstereotyped responses in the Kenyon cells (KCs). Theory and experiment suggest that this transformation is implemented by random connectivity between KCs and PNs. However, this hypothesis has been challenging to test, given the difficulty of mapping synaptic connections between large numbers of brain-spanning neurons. Here, we used a recent whole-brain electron microscopy volume of the adult fruit fly to map PN-to-KC connectivity at synaptic resolution. The PN-KC connectome revealed unexpected structure, with preponderantly food-responsive PN types converging at above-chance levels on downstream KCs. Axons of the overconvergent PN types tended to arborize near one another in the MB main calyx, making local KC dendrites more likely to receive input from those types. Overconvergent PN types preferentially co-arborize and connect with dendrites of αβ and α{\textquoteright}β{\textquoteright} KC subtypes. Computational simulation of the observed network showed degraded discrimination performance compared with a random network, except when all signal flowed through the overconvergent, primarily food-responsive PN types. Additional theory and experiment will be needed to fully characterize the impact of the observed non-random network structure on associative memory formation and recall.

}, issn = {1879-0445}, doi = {10.1016/j.cub.2022.06.031}, author = {Zheng, Zhihao and Li, Feng and Fisher, Corey and Ali, Iqbal J and Sharifi, Nadiya and Calle-Schuler, Steven and Hsu, Joseph and Masoodpanah, Najla and Kmecova, Lucia and Kazimiers, Tom and Perlman, Eric and Nichols, Matthew and Li, Peter H and Jain, Viren and Bock, Davi D} } @article {47062, title = {Quantitative neuroanatomy for connectomics in Drosophila.}, journal = {eLife}, year = {2016}, month = {2016 Mar 18}, pages = {e12059}, abstract = {

Neuronal circuit mapping using electron microscopy demands laborious proofreading or reconciliation of multiple independent reconstructions. Here, we describe new methods to apply quantitative arbor and network context to iteratively proofread and reconstruct circuits and create anatomically enriched wiring diagrams. We measured the morphological underpinnings of connectivity in new and existing reconstructions of\ Drosophila\ sensorimotor (larva) and visual (adult) systems. Synaptic inputs were preferentially located on numerous small, microtubule-free {\textquoteright}twigs{\textquoteright} which branch off a single microtubule-containing {\textquoteright}backbone{\textquoteright}. Omission of individual twigs accounted for 96\% of errors. However, the synapses of highly connected neurons were distributed across multiple twigs. Thus, the robustness of a strong connection to detailed twig anatomy was associated with robustness to reconstruction error. By comparing iterative reconstruction to the consensus of multiple reconstructions, we show that our method overcomes the need for redundant effort through the discovery and application of relationships between cellular neuroanatomy and synaptic connectivity.

}, doi = {10.7554/eLife.12059}, author = {Schneider-Mizell, Casey M. and Gerhard, Stephan and Longair, Mark and Kazimiers, Tom and Li, Feng and Zwart, Maarten and Champion, Andrew and Midgley, Frank and Fetter, Richard D and Saalfeld, Stephan and Cardona, Albert} }