Professor Iiris Hovatta: Investigating the genetics of anxiety

The recipe for the anxiety medication of tomorrow may reside in the brain of mice. However, uncovering it requires stressing on the creatures.

The mouse feels anxious. It has been placed inside the territory of a larger and more aggressive mouse with no way out. It has to experience anxiety for five minutes, until a dividing wall is lowered between the mice. But the wall does not prevent the mouse from seeing and smelling its oppressor.

And the torment does not end there. The day after, the mouse is again subjected to stress. And the day after that. According to professor of behavioural genetics Iiris Hovatta, who is heading the experiment, this will go on for ten consecutive days.

The mechanisms of anxiety are the same in mice and humans.

However, the mouse is not being stressed without a reason.

Hovatta and her research group are investigating the genetic predisposition to stress-induced anxiety. The experiment is aimed at creating an anxiety-arousing situation for the mouse resembling, for example, bullying at school.

Ten days later, the brain of the mouse will be dissected and closely examined.

“Becoming anxious is such a fundamental reaction that its mechanisms are the same in mice and humans. Therefore, mice help us study on a molecular level the effect of prolonged anxiety on the brain.”

Several mouse populations are used in the study, some of which get easily anxious, while others recover quicker. Through comparisons, Hovatta’s group aims to describe the neural connections affecting the genesis of stress-induced anxiety.

“Anxiety disorders are the second-most common cerebral dysfunction after migraine. If we come to understand their mechanisms, we will be able to develop better therapies.”

One promising research line could be myelin, which generates the membrane sheaths isolating neurons in the brain. In mice, the genes regulating the thickness of this membrane seem to react to anxiety. Hovatta hypothesises that changes in the thickness of the myelin membrane have an effect on the dialogue between various brain regions. The relative smoothness of this dialogue may relate to the development of anxiety.

“The white matter of the brain is more adaptable than we had thought. For a long time, myelin was considered merely a support structure, but it most likely plays a larger role in brain function,” Hovatta explains.

“Now we just have to come up with a method to test this hypothesis in practice.”