A brain consists of countless nerve cells and synaptic connections. In this project, we are reconstructing for the first time the connections of all neurons and their connections in the Drosophila larval brain. The fully reconstructed brain circuitry is also referred to as the connectome.
Project
Associating sensory stimuli with positive or negative reinforcements is essential for the survival of animals and humans. But how and where in the brain do such associations take place? Unfortunately, there are no complete reconstructions of brain regions containing all nerve cells and synaptic connections for learning and memory centers. Therefore, we initiated this project to reconstruct all this information for a brain region—the larval mushroom body.
Approach
Therefore, in this project, we have fully reconstructed the larval mushroom body at a cellular and synaptic level in a 3D volume based on an electron microscopy-scanned complete larval brain. In doing so, we have identified a series of previously unknown wiring patterns that repeat in each mushroom body compartment:
- Reciprocal connections between mushroom body neurons and modulatory input cells.
- Modulatory input cells to output cells.
- A surprisingly high number of connections between mushroom body neurons.
Aim
The newly discovered stereotypical wiring patterns could enhance the selection of learned behaviors. With the complete synaptic wiring map of the mushroom body, functional studies can now be designed for the first time to systematically investigate the neuronal principles of learning and memory.
Publications
Recurrent architecture for adaptive regulation of learning in the insect brain
Eschbach C, Fushiki A, Winding M, Schneider-Mizell CM, Shao M, Arruda R, Eichler K, Valdes-Aleman J, Ohyama T, Thum AS, Gerber B, Fetter RD, Truman JW, Litwin-Kumar A, Cardona A, Zlatic M.
Nat Neurosci. 2020 Apr;23(4):544-555.
DOI: 10.1038/s41593-020-0607-9
Connectomics and function of a memory network: the mushroom body of larval Drosophila
Thum AS, Gerber B.
Curr Opin Neurobiol. 2019 Feb;54:146-154.
DOI: 10.1016/j.conb.2018.10.007
Functional architecture of reward learning in mushroom body extrinsic neurons of larval Drosophila
Saumweber T, Rohwedder A, Schleyer M, Eichler K, Chen YC, Aso Y, Cardona A, Eschbach C, Kobler O, Voigt A, Durairaja A, Mancini N, Zlatic M, Truman JW, Thum AS, Gerber B.
Nat Commun. 2018 Mar 16;9(1):1104.
DOI: 10.1038/s41467-018-03130-1
The complete connectome of a learning and memory centre in an insect brain.
Eichler K, Li F, Litwin-Kumar A, Park Y, Andrade I, Schneider-Mizell CM, Saumweber T, Huser A, Eschbach C, Gerber B, Fetter RD, Truman JW, Priebe CE, Abbott LF, Thum AS, Zlatic M, Cardona A.
Nature. 2017 Aug 9;548(7666):175-182.
DOI: 10.1038/nature23455