4 — Electron Microscopic Reconstruction of Functionally Identified Cells in a Neural Integrator

This very recent paper discusses one particular neural circuit — the circuit in charge of moving eyes (oculomotion) to match the movement of a moving visual stimulus — and characterizes inter-integrator synapses (positive-feedback synapses between integrator neurons, likely charged with integrating signals over time or cell populations). Notably, this study collates results from two-photon (Ca++) imaging as well as serial electron-microscopy modalities.

My knowledge is limited about Zebrafish, the well-studied organism in which this study takes place — but I found the methods interesting and germane to my own work in multimodal mammalian studies: I imagine that, like many other cutting-edge teams, this team struggled with the onerous task of hand-annotating neuromorphology (using manual “tracing” annotation tools to mark up the EM data).

Biologically speaking: Interesting to me that contralaterally and ipsilaterally projecting neurons differed so much in dendritic morphologies and synaptic site locations. I wonder if this is an indication that — in zebrafish at least — contralateral projections are integrated with the rest of the circuit indirectly, possibly on an interneuron with a wide arbor that better (spatially) colocates a stimulus representation between hemispheres.

Kudos to the team for uploading all neural trace-data products to NeuroMorpho where they are freely available for download.