A connectomics-based taxonomy of mammals
- McGill University, Canada
- Tel Aviv University, Israel
- Vrije Universiteit Amsterdam, Netherlands
- Indiana University, United States
- Mila - Quebec Artificial Intelligence Institute, Canada
Abstract
Mammalian taxonomies are conventionally defined by morphological traits and genetics. How species differ in terms of neural circuits and whether inter-species differences in neural circuit organization conform to these taxonomies is unknown. The main obstacle for the comparison of neural architectures have been differences in network reconstruction techniques, yielding species-specific connectomes that are not directly comparable to one another. Here we comprehensively chart connectome organization across the mammalian phylogenetic spectrum using a common reconstruction protocol. We analyze the mammalian MRI (MaMI) data set, a database that encompasses high-resolution ex vivo structural and diffusion magnetic resonance imaging (MRI) scans of 124 species across 12 taxonomic orders and 5 superorders, collected using a unified MRI protocol. We assess similarity between species connectomes using two methods: similarity of Laplacian eigenspectra and similarity of multiscale topological features. We find greater inter-species similarities among species within the same taxonomic order, suggesting that connectome organization reflects established taxonomic relationships defined by morphology and genetics. While all connectomes retain hallmark global features and relative proportions of connection classes, inter-species variation is driven by local regional connectivity profiles. By encoding connectomes into a common frame of reference, these findings establish a foundation for investigating how neural circuits change over phylogeny, forging a link from genes to circuits to behaviour.
Data availability
The MaMI data set was originally collected and analyzed by Assaf and colleagues in Assaf, Y. et al., 2020 , Nat. Neurosci. (doi: https://doi.org/10.1038/s41593-020-0641-7). We have included the connectivity matrices used in this study in a public repository available at \url{https://doi.org/10.5281/zenodo.7143143}.
Article and author information
Author details
Funding
Natural Sciences and Engineering Research Council of Canada
- Bratislav Misic
National Science Foundation - BSF
- Yaniv Assaf
Canadian Institutes of Health Research
- Bratislav Misic
Fondation Brain Canada (Future Leaders Fund)
- Bratislav Misic
Canada Research Chairs
- Bratislav Misic
Michael J. Fox Foundation for Parkinson's Research
- Bratislav Misic
Healthy Brains for Healthy Lives
- Bratislav Misic
Natural Sciences and Engineering Research Council of Canada
- Guillaume Lajoie
Canada Research Chairs
- Guillaume Lajoie
Canadian Institute for Advanced Research
- Guillaume Lajoie
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Suarez et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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A connectomics-based taxonomy of mammals
eLife 11:e78635.
https://doi.org/10.7554/eLife.78635
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