Professor Dr Karl Deisseroth

Main areas of research: Optogenetics, CLARITY method (Clear Lipid-exchanged Anatomically Rigid/Immunostaining-compatible Tissue Hydrogel), Channelrhodopsin, Channelrhodopsin-2, neurological diseases, depression, autism diseases
Karl Deisseroth was one of the founders of optogenetics and also developed the CLARITY method. Unimagined insights into the brain have been gained through the use of both methods. Deisseroth hopes that these will then lead to a greater understanding of neurological diseases.
Optogenetics is a combination of optics and genetics. Proteins that react to light (channelrhodopsin) like, for example, those that are found in green algae, are introduced into nerve cells with the aid of a virus. The proteins act like a light switch by which the nerve cells in the brain can be externally controlled. Deisseroth was able to demonstrate his method on living animals. His team used viruses to implant the blueprint for the gene channelrhodopsin-2 in the brains of mice. When exposed to a certain light, the switch opened an ionic channel and the nerve cells fired signals. For the first time, researchers were thus able to selectively turn nerve cells on and off.
In the case of the mice, neurons that utilize dopamine could be turned on and off, which meant that the symptoms of Parkinson’s disease could possibly be palliated. Deisseroth hopes that his method will lead to a better understanding of neurological diseases like depression, anxiety disorders and Parkinson’s disease. What is more, he has been able to gain new insights into motivation, aggression and addiction. In the meantime, working groups all over the world are doing research using the optogenetic method.
The second method developed by Deisseroth is called the CLARITY method (Clear Lipid-exchanged Anatomically Rigid/immunostaining-compatible Tissue hydrogel). The team headed by Karl Deisseroth has succeeded in making the brain “transparent”. Brain tissue is immersed in a hydrogel and the lipids are dissolved out. What remains is a realistic, transparent brain-hydrogel hybrid. This allows post-mortem tissue to be investigated in its anatomic structure. In this way an entire brain of a mouse with all its nerve connections and cellular details can be made transparent. The method also has implications for cancer research.
In addition to his work in the lab, Karl Deisseroth continues practicing psychiatry. He treats patients with severe therapy-resistant depression and autism. His research is primarily undertaken for the benefit of his patients. He seeks to identify the neural networks that are impaired by psychiatric diseases. For this he plans on combining the optogenetic and CLARITY methods in the future.