Posted on May 25, 2017
Dr. Alapakkam Sampath, PH.D. is a Professor of Ophthalmology and Neurobiology at UCLA, and Associate Director of the Jules Stein Eye Institute. He is an internationally known visual neuroscientist who is recognized as a leader in the study of cellular and circuit level visual processing. His work focuses on signal transmission between photoreceptor cells, the rods and cones, and bipolar cells to determine how information is processed within retinal circuits and gives rise to visual perceptual sensitivity. Not only is his work of broad fundamental scientific interest, it has significant implications for our understanding of visual blinding diseases such as night blindness.
Sam gave Rotary an interesting engaging presentation on the eye. Of all the information that comes to the brain, over 2/3 comes through the vision. The eye has similar architecture in all living species. The transparent structure suspended behind the iris that helps to focus light on the retina; it primarily provides a fine-tuning adjustment to the primary focusing structure of the eye, which is the cornea.
There are two types of photoreceptors in the human retina, rods and cones. Rods are responsible for vision at low light levels. They do not mediate color vision, and have a low spatial acuity. The central fovea is populated exclusively by cones.
For 20 years, Dr. Sampath’s lab has been focused on how signals are processed in the eye, looking for ways to restore vision.  Optogenetics is a biological technique, which involves the use of light to control cells in living tissue, typically neurons that have been genetically modified to express light-sensitive ion channels. He showed 3 videos of blind mice finding their way out of a maze. Feeding a blind mouse with certain types of algae provides rudimentary vision. Therapies are emerging from this basic science.
Dr. Sampath’s lab is also looking for other ways to restore vision: nanotechnology, stem cells, retinal implants and the like.