Photoreceptors

Abnormal vasculature in the retina, specifically tortuous blood vessels, are common to many of the most prevalent retinal degenerative diseases currently affecting millions across the world. The mechanisms of their formation and development in the context of retinal degenerative disease, however, are still poorly understood. The rd1 and rd10 mice are relatively well-studied animal models of retinal degenerative disease, however, there lacks a systematic characterization of vascular changes co-related to photoreceptor degeneration in the rd1 and rd10 retina. Here, we utilize advancements in confocal microscopy, immunohistochemistry, and image analysis software in order to systematically characterize vascular changes before and after retinal development in the rd1 and rd10 mice. We show that there are plexus specific changes in the retinal vasculature that parallel photoreceptor degeneration. Such information will be of particular use to future studies investigating the role of vascular changes in retinal degenerative disease therapies.

Little is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles could detect. Second, I used food to train older turtles to swim toward one light color, and then to discriminate between the rewarded light and another light color ; lights were presented at intensities equally above the phototaxis threshold. Lastly, I varied light intensity so that brightness could not be used as a discrimination cue. Six turtles completed this task and showed a clear ability to select a rewarded over a non-rewarded color, regardless of stimulus intensity. Turtles most rapidly learned to associate shorter wavelengths (blue) with food. My results clearly show loggerheads have color vision. Further investigation is required to determine how marine turtles exploit this capability.