ABSTRACT
Cephalopods have large and complex brains, and in particular a highly capable visual system.
However, their brains evolved independently from vertebrates, and very little is known about how neural
circuits in the cephalopod brain process visual information. In fact, there has never been a direct
recording of receptive fields in the central visual system of cephalopods. This study will measure
neural activity and visual coding in the optic lobe of Octopus bimaculoides, an emerging model
organism for cephalopod research. The first aim will employ two-photon calcium imaging in the optic
lobe of juvenile octopuses, combined with controlled visual stimuli, to measure receptive field properties
in large ensembles of individual neurons. The second aim will combine this functional imaging with
anatomical connectivity, identified via retrograde tracing, to determine how visual information is routed
through the visual system and into higher brain regions associated with specific behaviors. The third
aim will incorporate these experimental results into computational analysis of the visual features being
encoded, and into network models of visual processing. Together, these aims will provide direct insight
into the neural coding and functional organization of this unique visual system.
This work will be the first to describe neural computations in the central visual system of cephalopods.
Examination of a system that is evolutionarily distinct, yet functionally parallel to the vertebrate system,
has the potential to illuminate novel ways by which visual processing can be carried out. Likewise,
observation of convergence of functional organization in cephalopods, relative to vertebrates and other
invertebrates, such as Drosophila, would help identify key features necessary for the function of
complex visual systems.