It is one of the great dreams of brain research to visualize at once all nerve cells and their connections of a complete brain in 3D. Scientists of the Max Planck Institute of Psychiatry in Munich and the Vienna University of Technology (TU Vienna) have now come a step closer to turning this dream into reality.

They have succeeded in making whole mouse brains transparent and then to reconstruct parts of their neuronal networks with a computer. During their investigations at the MPI of Psychiatry they put mouse brains in an oil solution which rendered the brains completely transparent, as now published in Nature Methods. They transilluminated these transparent brains with a laser from the side layer by layer. This way, green fluorescence was induced in genetically marked nerve cells. Using the many images from their "ultramicroscope" the scientists in the research group of the medical doctor and physicist Hans-Ulrich Dodt were able to reconstruct parts of the neuronal network in three dimensions, comparable to computer tomography but with much higher resolution.

Prof. Dodt who was appointed to the chair of Bioelectronics of the TU Vienna in January, plans to utilize this method to investigate the complex neuronal networks of the cortex. The scientists are interested to see if it is possible to visualize alterations at nerve cells after learning using this method. Ultramicroscopy will also be used to investigate the development of neuronal diseases like Alzheimer`s in mice. Besides science, the technique also has an aesthetic aspect: One can simulate a fly-through the brain using the recorded data. Therefore in the future the technique of the glass brain will be used probably for teaching students employing a "Playstation Brain".

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