Dopamine regulates pleasure and anxiety memory through the happiness hormone?

Happiness hormone dopamine also controls fear memory

Fear and luck seem as contradictory as day and night. However, researchers have recently found in a study that the hormone dopamine, which was previously known only to induce happiness, also ensures that threatening events in the brain more pronounced.

The research team included scientists from the Otto von Guericke University Magdeburg and neurobiologists from the Research Institute for Molecular Pathology (IMP) in Vienna. So far, the happiness hormone dopamine has primarily been used as a mediator of reward and motivation in the brain. The scientists now found that it also plays an essential role in storing threatening events. The results of the study were recently published in the journal "Nature Neuroscience".

Dopamine - Is the same hormone that gives us pleasure and motivation also responsible for the memory of fear and terror? (Image: studiostoks / fotolia.com)

Fear as a survival strategy

As an important emotion, fear and fear have ensured the survival of humanity and that of many animals. How anxiety arises is still not understood. Researchers in the latest study have come one step closer to deciphering the puzzle. For humans and animals, it is vital to memorize threatening events, so that they do not repeat as possible. The area responsible for this is fear memory.

Memories of fear and terror

Fear memory stores odors or sounds that we associate with the reoccurrence of dangerous situations. These could be, for example, sounds of an approaching fight or odors of poisonous food. In this way, we can respond appropriately to the situation to avoid or prepare for the danger.

Happiness and fear hand in hand

For humans, the distinction between dangerous and harmless environmental signals is an important survival role dar. The team around the neurobiologist Dr. med. Wulf Haubensak explored the question of which bodily processes contribute to our ability to build and recall this fear memory. Ironically, the happiness and motivational hormone dopamine appears to play a central role in these processes.

Discovered a new class of dopamine neurons

The scientists have gained their knowledge in experiments on mice. They played a certain tone as ambient stimulus to them. After that they received a mild electric shock in the foot. Using state-of-the-art high-tech methods, scientists were able to monitor mouse brains and identify a new class of dopamine neurons in the midbrain region. This was activated whenever the mice learned to store the relationship between tone and footshock in fear memory.

Emotional learning

Activation of the neurons also released dopamine into the brain. And right there, where the center for emotional learning in the mammalian brain, the so-called amygdala. According to the researchers, this led to a particularly effective storage of the now perceived as threatening tone in the long-term memory. The dopamine is much more than just the messenger of happiness, has already been recognized in past studies. However, these functionalities are still new medical ground.

Dopamine even more important than previously thought

"These findings shed new light on dopamine neurons, which until now have only been seen as a vehicle for reward and motivation," explains Dr. Florian Grössl, the first author of the publication, in a press release on the study results. The study identified a previously unknown neuronal network consisting of dopamine neurons and nerve cells of the amygdala, which is essential for the evaluation of emotions. According to Grössl, dopamine filters out the vital environmental stimuli and stores them in the memory.

From mice to humans?

The researchers report that in humans the dopamine neurons are linked to the amygdala in the same way as in mice. Scientists firmly believe that these processes are also controlled by dopamine in humans. This could be a groundbreaking finding for the treatment of mental disorders such as post-traumatic stress disorder or morbid anxiety. Future investigations will now show whether treatment with dopamine-like drugs is suitable as therapy for such diseases. (Vb)