Ann Morris from the University of Kentucky studies the zebrafish (Danio rerio). In particular, she studies the ability of zebrafish retinas to regenerate following retinal injury or damage. Retinal regeneration is an interesting phenomenon that mammalians seem to lack and yet zebrafish manage to do this despite having a retina that in many ways is far more complex than the mammalian retina.
NPR has a wonderful story of childhood friends, Henry Wanyoike and Joseph Kibunja who started running together as children 30 years ago and are still running in competition today. That is a remarkable story enough, but even more compelling is that Wanyoike is blind from a stroke that cost him his sight and Kibunja is his running guide.
It is a wonderful story and well worth the read. While there, also be sure to stop by the Henry Wanyoike Foundation website, designed to help bring young people together through sport.
We’ve talked about jumping spiders before here on Webvision as they are an amazing animal with very well developed vision. However, their retinas and visual pathways are very different from the vertebrate retinas in that they use image defocusing for depth perception rather than parallax like humans and other vertebrates do. Figuring out spider vision has been a long standing effort by a small group of scientists and one of the problems of observing spiders is figuring out how they scan. The movie above however shows a transparent jumping spider with the pigment cells in its eyes/retinas moving while they scan an image. There is another pretty impressive movie here, showing a microscopic view into the retina of a living jumping spider.
There is a short but fun post over on Knowing Neurons that looks to be part of a series on color and how color is perceived. Its got some great visuals by the guest author Raz and I can’t wait to see what she has to say about oppositional antagonism.
Benham’s Top or Benham’s disk is named after Charles Benham, a toy maker but also an amateur scientist who contributed and published articles to the likes of Nature. Benham’s observation with a toy top was relayed through an article in Nature in 1894 that described a visual phenomenon generated by a toy top painted like the above image. When spun, the Fechner color effect is perceived. Not everyone perceives the same colors…