The brain of the fly beats any computer
The electrical activity of individual nerve cells is usually measured with the aid of extremely fine electrodes. In the fly, however, most of the nerve cells are simply too small to be measured using this method. Nevertheless, since the fly is the animal model in which motion perception has been studied in most detail, the scientists were all the more determined to prize these secrets from the insect's brain. A further incentive is the fact that, 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. So it's no wonder that deciphering this system is a worth-while undertaking.
Fluorescence molecules and state-of-the-art microscopes
"We had to find some way of observing the activity of these tiny nerve cells without electrodes", Dierk Reiff explains 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.
To examine how the brains of fruit flies process motion, the neurobiologists presented the insects with moving stripe patterns on a light-diode screen. The nerve cells in the flies' brains react to these LED light impulses by becoming active, thus causing the luminance of the indicator molecules to change
|Contact: Stefanie Merker|