Incoming links: Neuron
A Drosophila melanogaster has about 135k neurons, and we only managed to reconstruct its connectome in 2023.
The human brain has 86 billion neurons, about 1 million times more. Therefore, it is obvious that we are very very far away from a full connectome.
Instead however, we could look at larger scales of connectome, and then try from that to extract modules, and then reverse engineer things module by module.
This is likely how we are going to "understand how the human brain works".
Some notable connectomes:
- 2019: 1mm cube of mouse brain: www.nature.com/articles/d41586-019-02208-0
- 2023: Drosophila connectome
The hard part then is how to make any predictions from it:
- 2024 www.nature.com/articles/d41586-024-02935-z Fly-brain connectome helps to make predictions about neural activity. Summary of "Connectome-constrained networks predict neural activity across the fly visual system" by J. K. Lappalainen et. al.
2024: www.nature.com/articles/d41586-024-03190-y Largest brain map ever reveals fruit fly's neurons in exquisite detail
As of 2022, it had been almost fully decoded by post mortem connectome extraction with microtome!!! 135k neurons.
- 2021 www.nytimes.com/2021/10/26/science/drosophila-fly-brain-connectome.html Why Scientists Have Spent Years Mapping This Creature’s Brain by New York Times
That article mentions the humongous paper elifesciences.org/articles/66039 elifesciences.org/articles/66039 "A connectome of the Drosophila central complex reveals network motifs suitable for flexible navigation and context-dependent action selection" by a group from Janelia Research Campus. THe paper is so large that it makes eLife hang.
This contains the C. elegans connectome.
The browseable thing is this massive interactive PDF: wormwiring.org/papers/Interactive-Diagram.pdf. It lists neurons from the C. elegans cell lineage using the standard cell names, and how they connect to each other. Some make a surprising ammount of connections.
