Glimpse of the brain What does happiness mean and what does it produce?

Happiness can not be reduced to a messenger substance

So far, scientists have assumed that the messenger substance dopamine plays a central role in perceived happiness, since it is always released from the reward system if you register a success or are happy about something. The latest research now shows that the process of happiness is apparently more complex than previously thought. In experiments, scientists have shown that dopamine seems to play only a minor role in luck.

A research team around Dr. Michael Lippert and PhD student Marta Brocka examined at the Leibniz Institute for Neurobiology (LIN) in Magdeburg how good luck can be measured. They assumed that it would be possible to glean good fortune from the dopamine release during an MRI imaging process. During the test series, they came to surprising results, which were recently published in the journal "Neurolmage".

What is luck? What philosophers have argued for millennia seems to be a source of controversy in science as well. At any rate, a German research team showed what happiness is not: easy to decipher. (Image: S.H.exclusiv / fotolia.com)

What is luck and what is not it?

From a philosophical point of view, this is the main theme of countless books and films. The Magdeburg scientists want to understand the mechanisms that take place in the brain, if you feel lucky. So far, the release of the neurotransmitter dopamine is considered to be fundamental to feelings of happiness. However, the results of the study indicate that a rethink in this area is needed.

The visibility of happiness

Patients with depression or addictions are known to have changes in the brain's reward system. So far, neuroscientists and physicians use functional magnetic resonance imaging (fMRI) to visualize such changes. Lippert and his team checked whether this method is actually suitable for such purposes and whether one can visualize luck in the MRI scanner.

Rats who are blacksmiths of their "luck"

In the animal model, the LIN researchers carried out experiments on genetically modified rats. The rodents were able to control their dopamine release in the brain. By independently operating a lever, they received so-called optogenetic stimulation, in which light pulses in the brain stimulate dopamine release. "In doing so, an extremely strong reward stimulus is triggered," says doctoral student Marta Brocka in a press release on the study results.

Imaging procedures should provide information

The animals were meanwhile examined with a small animal scanner to document which brain areas were activated as strongly as a result of the release. According to the researchers, the brain areas can be visualized with the help of imaging techniques in a high spatial resolution. "By taking pictures in the tomograph, we see changes in the circulation of the brain," explains Lippert. These would be based on metabolic processes, which in turn would be related to neuronal activity, so the brain expert.

Is the essence of happiness invisible?

In the course of the experiments, the team noted with astonishment that "the measurable effects of dopamine were very small despite the high reward value of the stimulation". In contrast, a comparison group in which additional brain areas were also stimulated showed clearer results. The scientists come to the conclusion: "The release of dopamine underlying the feelings of happiness is not directly measurable in the MRI." Instead, the total activation of the brain area is crucial. The essence of happiness remains invisible with this method.

For whom are the results relevant??

According to the authors of the study, the results could have a decisive influence on further research projects, as it has previously been assumed that dopamine in animals and humans have a great influence on the measured signals in the brain. "We have to say goodbye to the assumption that the activity changes in the brain that we see as a result of a reward are triggered directly by dopamine," summarizes study leader Lippert.

The role of dopamine in change

Also for the clinical area, the research results could be important, as an imbalance in dopamine levels is also seen as a possible cause of diseases such as Parkinson's, addiction or depression. Only recently, another study that had dopamine as a central theme appeared. It showed that also the fear memory is regulated by the happiness hormone. (Vb)