Swim Circuits
Neurons in sea slugs are individually identifiable based on their unique properties, such that one can find the very same neuron in each animal. This allows us to work out detailed circuit diagrams showing the connectivity of neurons and understand the fundamental mechanisms underlying behavior. Homologous neurons can also be identified in different species, allowing us to compare neural circuits across species. We researched these circuits for over 25 years but are no longer working on this topic.
The Tritonia swim network.
Below is the neural circuitry underlying the dorsal ventral (DV) swimming behavior in Tritonia. A full explanation of this circuit can be found in the Scholarpedia article.
The Melibe swim central pattern generator
Below is the neural circuitry underlying the left-right (LR) swimming behavior of Melibe. See Sakurai et al. 2014.
The Dendronotus swim CPG
Below is the neural circuitry underlying the LR swimming behavior of Dendronotus. See Sakurai and Katz, 2022 and Sakurai and Katz, 2016
Although the CPG underlying Tritonia swimming consists of different sets of neurons than the other species, some of the homologous neurons have been found in the other species. The DV swim CPG neurons, DSI and C2, have effects on the LR swim CPG in Melibe and other LR swimmers. See Newcomb et al. 2012.
Melibe and Dendronotus are both LR swimmers. Phylogenetic analysis suggests that the behavior is homologous. But, the circuits differ. See Sakurai et al. 2011.
We have shown that rewiring the Dendronotus swim CPG into the Melibe configuration using the Dynamic Clamp technique allows it to function like Melibe. See Sakurai and Katz, 2017.