How fly manages to perceive motion in fractions of a second

LONDON - For the first time, researchers at the Max Planck Institute of Neurobiology have successfully established the necessary technical conditions for decoding the underlying mechanisms of how the fly manages to perceive visual movements in only fractions of a second.

And the first analyses of this motion vision in flies have shown that a great deal more remains to be discovered.

Back in 1956, a mathematical model was developed that predicts how movements in the brain of the fly are recognized and processed.

However, it is still unclear which nerve cells are wired to each other in the fly brain for the latter to function as predicted in the model.

“We simply did not have the technical tools to examine the responses of each and every cell in the fly’s tiny, but high-powered brain”, Nature quoted Dierk Reiff as saying.

That is hardly surprising, considering the minute size of the brain area that is responsible for the fly’s motion detection.

Albeit the number of nerve cells in the fly is comparatively small, they are highly specialized and process the image flow with great precision while the fly is in flight.

Flies can therefore process a vast amount of information about proper motion and movement in their environment in real time - a feat that no computer, and certainly none the size of a fly’s brain, can hope to match.

“We had to find some way of observing the activity of these tiny nerve cells without electrodes”, Reiff explained one of the challenges that faced the scientists.

In order to overcome this hurdle, the scientists used the fruit fly Drosophila melanogaster and some of the most up-to-date genetic methods available.

They succeeded in introducing the indicator molecule TN-XXL into individual nerve cells.

By altering its fluorescent properties, TN-XXL indicates the activity of nerve cells.

“At long last, after more than 50 years of trying, it is now technically possible to examine the cellular construction of the motion detector in the brain of the fly”, reports a pleased Alexander Borst, who has been pursuing this goal in his department for a number of years.

Now that the first step has been taken, the scientists intend to examine - cell by cell - the motion detection circuitry in the fly brain to explain how it computes motion information at the cellular level.

The study is published in Nature Neuroscience. (ANI)