Retinal Connectomics: Toward Complete, Accurate Networks

Retinal Connectomics

We have a new publication, Retinal connectomics: Toward complete, accurate networks in Progress in Retinal and Eye Research.  Authors are:  Robert E. Marc, myself, Carl B. Watt, Crystal Sigulinsky, James R. Anderson and J. Scott Lauritzen.

Connectomics is a strategy for mapping complex neural networks based on high-speed automated electron optical imaging, computational assembly of neural data volumes, web-based navigational tools to explore 1012-1015 byte (terabyte to petabyte) image volumes, and annotation and markup tools to convert images into rich networks with cellular metadata. These collections of network data and associated metadata, analyzed using tools from graph theory and classification theory, can be merged with classical systems theory, giving a more completely parameterized view of how biologic information processing systems are implemented in retina and brain. Networks have two separable features: topology and connection attributes. The first findings from connectomics strongly validate the idea that the topologies complete retinal networks are far more complex than the simple schematics that emerged from classical anatomy. In particular, connectomics has permitted an aggressive refactoring of the retinal inner plexiform layer, demonstrating that network function cannot be simply inferred from stratification; exposing the complex geometric rules for inserting different cells into a shared network; revealing unexpected bidirectional signaling pathways between mammalian rod and cone systems; documenting selective feedforward systems, novel candidate signaling architectures, new coupling motifs, and the highly complex architecture of the mammalian AII amacrine cell. This is but the beginning, as the underlying principles of connectomics are readily transferrable to non-neural cell complexes and provide new contexts for assessing intercellular communication.

2 Replies to “Retinal Connectomics: Toward Complete, Accurate Networks”

  1. Just heard Robert’s seminar on Connectomics here. I read the PRER paper prior to the seminar to get a bit of a leg up. Graph theory will require some more study on my part… Clearly it is the only way to tackle a problem of this complexity (10 to the power of 80 connections in the human brain!) and the days of the solitary microscopist taking a few images here and there are over, at least in this field. He mentioned the sociology and politics of connectomics: perhaps a lack of understanding on the part of some who should know better?! I think his words on pathoconnectomics left a few in the audience a bit dismayed- that cell based therapies, chips, etc., will not help in a remodeling retina once on its way and that remodeling has to be stopped early and that we have to figure out how/when to stop remodeling in degenerating retina. Lots of food for thought!

    1. Hey Michael,

      Thanks for the review of the talk. Connectomics is an amazing approach for sure, but the scary thing is how much it shows us we do not know about many systems that were thought to be well understood. The future is more complicated (and exciting) than we thought I suppose…

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