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Department of Biological Sciences

Drs. Dan Chappell and Dan Speiser published a new study in the Journal of Experimental Biology

Animals with distributed visual systems, such as species of cnidarians, molluscs, annelids, and echinoderms, have arrays of many separate photoreceptive organs dispersed across their bodies. The marine mollusc Acanthopleura granulata (chiton) is one of them and has a distributed visual array composed of hundreds of small image-forming eyes embedded within its eight dorsal shell plates. How A. granulata and other animals with distributed visual systems process visual information remains poorly understood. In their latest study titled "Polarization sensitivity and decentralized visual processing in an animal with a distributed visual system", former graduate student Dr. Daniel Chappell and his mentor Dr. Dan Speiser explored the visually mediated behaviors and neuroanatomy of the eyed chiton A. granulata. Using behavioral experiments to investigate the visual capabilities of A. granulata, the authors found that chitons have a spatial vision with an angular resolution of 6 degrees and respond to looming stimuli defined by contrasting angles of linear polarization. Using dye labeling and immuno-histochemistry approaches, the authors further defined the location of visual integration within the chiton nervous system. Results from this study suggest that A. granulata effectuates its visually mediated behaviors using a unique processing scheme: it extracts spatial and polarization information using a distributed visual system, and then integrates and processes that information using decentralized neural circuits. Congrats!

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