Periodic cone cell twists in the walleye, Stizostedion vitreum; a new type of retinomotor activity.
A typical retinomotor movements (RM) have been found in a localized area of the retina of the walleye, Stizostedion vitreum. The ellipsoid and outer segment of regions of twin cones in an oblong region of the central retina rotate, twisting about their axes at intervals throughout the 24 hr day. This twist results in a local, cyclic change of the cone mosaic, from the predominant row type to a square type. The cone cell myoids extend slightly, but the cone ellipsoids remain relatively close to the outer limiting membrane (OLM). Throughout the retina, rod cells exhibit ubiquitous extension and contraction of their myoid regions coincident with changes in illumination as is typical of fishes with duplex retinas. These retinomotor movements first appear around 6 weeks of age, and persist throughout growth, becoming more pronounced with maturity. Stizostedion vitreum is the first fish observed with this type of cone RM activity.
Wahl
C M
CM
Section of Ecology and Systematics, Cornell University, Ithaca, NY 14853.
D000375:Aging / Q000502:physiology; D000818:Animals; D002452:Cell Count; D002465:Cell Movement; D005399:Fishes / Q000502:physiology*; D008027:Light; D012160:Retina / Q000502:physiology* / Q000648:ultrastructure; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012399:Rotation