Is fear taught or is it genetic?

 

Palpitations, accelerated breathing, cold sweats and other symptoms, triggered by stimuli that do not disturb healthy people at all, make the lives of people with all kinds of anxiety disorders a pain. In Europe, 18 percent of the population suffered from anxiety disorders last year which among others Phobias, panic disorders or post-traumatic stress disorder count. Morbid anxiety is not only a major health and social problem, it also increases the risk of becoming addicted to drugs. On the one hand, pathological fear is genetically determined; on the other hand, environmental factors such as traumatic experiences always play a role. From a neurobiological point of view, there is a malfunction of various neurotransmitters, messenger substances that are responsible for the transmission of information between nerve cells. "Above all, through imaging processes we know that certain areas of the brain are activated differently in people who suffer from anxiety than in healthy people," explains ao. Univ.-Prof. Nicolas Singewald from the Institute for Pharmacy at the University of Innsbruck. He has been researching fear mechanisms successfully for many years and is instrumental in the research by Univ.-Prof. Jörg Striessnig coordinated the large special research area of ​​the Austrian Science Fund (FWF F44), in which cell signaling pathways in connection with disorders of the central nervous system are examined. "Although the amygdala, as the core area of ​​the brain where emotional sensations are processed, is an important output station for fear, there is not a fear center in the brain, but a whole network of areas interacts," explains Singewald. The neuropharmacologist is an associate member of the inter-university neuroscientific doctoral program SPIN. Univ.-Prof. Gerald Zernig, who works at the Department of Experimental Psychiatry at the Medical University with new therapy options for drug addicts. “There is great overlap in the neural networks that process stress, fear, other emotions and, of course, addictive behavior. That is why it is so interesting to combine our expertise in a research project ”, says Singewald about the cooperation with his colleague from the Medical University. “There is still a lot of room for improvement in the treatment of addiction disorders. The only drug treatment that is successful is the use of substitute drugs. Addicts can benefit from psychotherapy, but I know from many conversations that addicts are immensely afraid of social interaction, ”says Zernig, who works as a psychotherapist himself.

Mapping the brain

According to Zernig, the problem with pharmacological treatment is that although one knows which brain regions are affected, the responsible groups of nerve cells have not yet been identified. Using immunohistochemical and molecular biological methods, Zernig and Singewald want to map the functions of those areas of the brain that are involved in anxiety and drug addiction down to the last nerve cell, which is known as functional mapping. This is possible using a mouse model developed and established by the Max Planck Institute for Psychiatry (Munich), which is based on the breeding of highly, normal and less anxious strains of mice. “Our vision is to find exactly those neuron ensembles that are over-activated, and then to intervene in a targeted manner and bring them to normal levels in order to make drugs less attractive. This is very important for drug cessation and relapse prevention, ”says Zernig.

Different addictive behavior

In anxiety patients, neuronal changes can be detected in certain regions of the brain, which make drug addiction more likely later on. The same regions are then also affected by the addiction. The Innsbruck researchers were also able to show this in connection with fear and cocaine. “But we also know from our research that neuronal changes in the brain can at least partially be reversed. We want to investigate which more specific pharmacological and behavioral therapeutic approaches can be used sensibly in the future, ”says Singewald, describing the further goals of the research project. Simone Sartori (Uni) and Constanze Barwitz (Medical University) are significantly involved. The focus is on two areas of the brain that are affected by neuronal changes in both anxiety disorders and drug addiction: the nucleus accumbens and the prefrontal cortex. While the nucleus accumbens can be described in an extremely simplified way as a reward center, the prefrontal cortex is responsible for behavior and reaction control and thus also for delaying the reward. The consumption of cocaine prevents the re-uptake of dopamine, noradrenaline and serotonin and causes an increased concentration of these messenger substances in the reward system, which is thus "flooded". At some point, however, the neurotransmitter stores are emptied and the system needs a break. Then, among other things, extreme anxiety. “We want to break this vicious circle. The way to get there is through functional mapping ”, say the experts.

Ao. Univ.-Prof. Nicolas Singewald heads the neuropharmacology research group in the pharmacology and toxicology department. One of his main focuses is the development of anti-anxiety drugs.
Ao. Univ.-Prof. Gerald Zernig heads the addiction research team at the Department of Experimental Psychiatry and also works as a psychotherapist with drug patients.

This article appeared in the February issue of the magazine “wissenswert”. A digital version is available here (PDF).