Now, in a paper in this week's issue of the journal Nature, biologists at the University of California, Berkeley, have finally detailed the cellular circuit responsible for motion detection in the eye's retina.
This circuit, which enables us to track moving objects, serves as an example of other brain circuits, some of which perform thousands of computations every second. The findings could aid the design of bionic eyes that track motion and process visual information like our own eyes.
"This work reveals a very sophisticated neural computation, the first non-linear computation performed by the nervous system for which a circuit is close to being solved," said Frank Werblin, professor of molecular and cell biology at UC Berkeley. "It is a preliminary step in understanding how more sophisticated computations are performed by the brain."
Werblin notes, for example, that we use motion detection every time we cross the street, anticipating when traffic will reach our intersection and deciding when to cross.
"Barry Bonds probably has superior motion-detecting neurons," he added, referring to the home-run hitter with the San Francisco Giants. "He takes a simple movement detector and, in the context of a highly sophisticated action, uses it, along with about a million other computations, both sensory and motor, to make contact with the ball."
The technically demanding experiments measuring the output of cells in the retina were conducted in Werblin's laboratory by graduate students Shelley I. Fried of the School of Optometry's Graduate Group in Vision Science and Thomas A. Mnch of the Helen Wills Neuroscience Institute. All are members of UC Berkel
Contact: Robert Sanders
University of California - Berkeley