Functional organization of visual responses in the octopus optic lobe

• Published in: Current biology 2023-07, Vol.33 (13), p.2784-2793.e3
• Main Authors: Pungor, Judit R., Allen, V. Angelique, Songco-Casey, Jeremea O., Niell, Cristopher M.
• Format: Article
• Language: English
• Subjects: Animals; cephalopod; ecological vision; Eye; luminance; Nervous System; Octopodiformes; receptive fields; retinotopy; Visual Pathways - physiology; Visual Perception
• ISSN: 0960-9822; 1879-0445; 1879-0445
• DOI: 10.1016/j.cub.2023.05.069

Cephalopods are highly visual animals with camera-type eyes, large brains, and a rich repertoire of visually guided behaviors. However, the cephalopod brain evolved independently from those of other highly visual species, such as vertebrates; therefore, the neural circuits that process sensory information are profoundly different. It is largely unknown how their powerful but unique visual system functions, as there have been no direct neural measurements of visual responses in the cephalopod brain. In this study, we used two-photon calcium imaging to record visually evoked responses in the primary visual processing center of the octopus central brain, the optic lobe, to determine how basic features of the visual scene are represented and organized. We found spatially localized receptive fields for light (ON) and dark (OFF) stimuli, which were retinotopically organized across the optic lobe, demonstrating a hallmark of visual system organization shared across many species. An examination of these responses revealed transformations of the visual representation across the layers of the optic lobe, including the emergence of the OFF pathway and increased size selectivity. We also identified asymmetries in the spatial processing of ON and OFF stimuli, which suggest unique circuit mechanisms for form processing that may have evolved to suit the specific demands of processing an underwater visual scene. This study provides insight into the neural processing and functional organization of the octopus visual system, highlighting both shared and unique aspects, and lays a foundation for future studies of the neural circuits that mediate visual processing and behavior in cephalopods. [Display omitted] •The functional organization of the cephalopod visual system is largely unknown•Using calcium imaging, we mapped visually evoked responses in the octopus optic lobe•We identified spatially localized receptive fields with retinotopic organization•ON and OFF pathways were distinct and had unique size selectivity properties Pungor et al. use calcium imaging to measure visually evoked response properties in the cephalopod central nervous system. They demonstrate shared and novel aspects of visual function in the octopus, including retinotopic organization, the emergence of ON and OFF pathways, and asymmetries in the processing of light and dark stimuli.