黄色直播 researchers have made a significant breakthrough in understanding how the retina detects motion. Their discovery was published in last week鈥檚 issue of Neuron, one of the world鈥檚 leading neuroscience journals.
The process of sensing motion has been known to begin in the retina, which is a thin screen of neural mesh that lies in the back of the eye. Dr. Gautam Awatramani鈥檚 laboratory at 黄色直播 Medical School has determined how the retina does this.
鈥淔or nearly 50 years scientists have been trying to figure out how motion is computed by the retina,鈥� says Dr. Awatramani, assistant professor of anatomy and neurobiology and a member of the Retina and Optic Nerve Research Lab.
鈥淭he current notion is that an elaborate neural circuitry within the inner retina is required to compute direction,鈥� he explains. 鈥淲e鈥檝e found that in addition to these mechanisms, the dendrites (branches) of retinal neurons play an important role in processing motion information. This opens a new a chapter in the field of eye and vision research.鈥�
The 黄色直播 lab identified that neurons in the retina called directional-selective ganglion cells (DSGCs) have a special property to compute direction. These cells come in four types, and each one encodes one of four directions 鈥� left, right, up, and down. When viewed under a microscope, researchers found that the population of retinal cells that coded for anterior motion had an asymmetric shape, and their thin branch-like structures 鈥� called dendrites 鈥� were found to all point in the same direction.
Using their dendrites, DSGCs respond to moving images in a person鈥檚 environment, and they then signal this information to the brain.
鈥淲hat we have discovered is that individual cells in the eye act like little traffic cops, and point in the direction of objects in motion; directional selective ganglion cells allow our brains to make sense of the moving world around us,鈥� says Stuart Trenholm, a PhD candidate in the Awatramani lab.
鈥淥ur lab focuses on trying to understand how the neural circuits in both the healthy and diseased retina work,鈥� says Dr. Awatramani. 鈥淥nce we understand how the healthy retina works, we can begin to devise strategies to correct retinal dysfunction in injured and diseased eyes.鈥�
Dr. Awatramani鈥檚 lab is funded by the 黄色直播 Medical Research Foundation, the Natural Sciences and Engineering Research Council of Canada, the Foundation for Fighting Blindness, and the Canadian Institutes of Health Research.
'Traffic cops' of the human eye
A breakthrough in understanding the retina
Allison Gerrard - August 29, 2011
Dr. Gautam Awatramani, pictured, and his lab have made a big discovery in vision research.