Octopuses are molluscs, like snails and clams, yet they have a large, complex brain capable of sophisticated and intelligent behavior. The human and octopus lineages diverged more than 500 million years ago, from a simple bilaterial ancestor with a very simple nervous system. Thus, the octopus brain evolved its complexity completely independently from our own. Little is known about how this "alien" brain is wired or how it carries out complex behaviour, especially at the level of molecules and circuits.
To study the structure of the octopus brain, we focus on the hatchling, a small, experimentally-tractable life stage whose nervous system resembles the much larger adult. The hatchling of the common octopus is 1-2 mm long, and its contain about 200,000 neurons (comparable to the number in Drosophila). In the wild these animals are planktonic, and to survive they exhibit robust behaviors including visually-guided hunting and escape, which are modified by learning and can be readily assayed in the lab. We are therefore interested in mapping the neural circuitry of the hatchling, thereby identifying new biology as well as conserved principles underlying complex behaviour.
In this project, we will use newly-developed expansion microscopy methods to map circuits in the octopus hatchling visual system, from the eye to the central brain. To identify cell types within these circuits, we will use probes against neuropeptides, whose diversity and specificity provides a bar code for neuronal identity. In parallel, we will characterise visually-guided behaviour in the hatchling, providing new insight into how these animals perceive their environment and what features their visual circuits detect. Finally, we will use in vitro electrophysiology and calcium imaging from hatchling brain slices to define the functional properties of neurons and circuits in the visual system.
References
Novel dopaminergic neurotransmission in the Octopus visual system
bioRxiv: (2025) preprint