Nerves can be blocked or redirected

What happens when nerve cells fail

Total brain failure

Strokes are just one of many diseases in which communication between nerve cells is interrupted. Micro-failures in the brain also occur in diseases such as depression and dementia. The function usually returns after a while, but consequential damage often remains, so that functionality can only be restored, if at all, through lengthy treatments. Researchers at FAU have therefore investigated what happens during this interruption phase and what ways there are to prevent permanent damage or to accelerate healing. They have published their findings in the renowned journal Scientific Reports (doi: 10.1038 / s41598-017-11729-5).

The researchers led by Jana Wrosch from the Chair of Psychiatry and Psychotherapy at FAU have found that during the blocked communication, strong change processes take place in the nerve cells. The nerve cell networks are reconnected and hypersensitive during the interruption. When the normal communication highways are blocked, there is a traffic chaos in the brain, in which the information is diverted in a disordered manner via branched back roads and new beaten tracks. Synapses are being created and put into operation everywhere. When the signal returns, there are no more orderly information routes and the functions have to be relearned like a child. Because the normal signals are missing during the interruption, the nerve cells also try to find their input again through increased sensitivity. If the signals then return, the nerve cells can overreact.

Dye makes nerve cells blink

It is a technical challenge to make the microscopic connections between the nerve cells visible. Microscopy methods commonly used up to now, such as electron microscopy, always require pre-treatment of the nerve cells that are being examined. The nerve cells die and the change processes in the cells cannot be observed. Wrosch's team therefore developed a high-speed microscopy method and special statistical computing software that makes it possible to make the communication networks of living nerve cells visible. To do this, a video is recorded of the cells, in which a picture is taken every 36 milliseconds. A special dye ensures that individual cells always flash when they have just received a signal. The software developed then recognizes these cells on the video images and determines the information paths through which signals are passed from cell to cell.

The nerve cells were treated with the puffer fish poison tetrodotoxin in order to simulate the communication blocks that occur during illnesses in the laboratory. After blocking phases of varying length, the researchers removed the poison from the cells and were able to analyze how the nerve cell networks had changed as a result of the treatment. "With these experiments we can finally make visible what is going on during the communication blockade," reports Wrosch. “Now we can try to develop drugs that prevent these harmful changes.” In the next few projects, the research team will concentrate on the precise mode of action of antidepressants on the nerve cell networks and try to find new approaches for better drugs.

Additional Information:

Jana Katharina Wrosch
Tel .: 09131 / 85-44294
[email protected]