Glimpse in the brain: Happiness is invisible: the release of dopamine happiness hormone remains hidden in the MRI

Even though it is so colorful and so happy in our heads, happiness does not necessarily appear to the brain.

© Butengultek / istock

Dopamine, known as the happiness hormone, is an important messenger of our nervous system. Among other things, it plays a central role in the reward system – and is distributed, for example, when a student is happy with a math 1. In diseases such as depression, Parkinson's disease or addictions, this brain-specific reward system is disrupted – they are often badociated with changes in dopamine levels or an inadequate function of that neurotransmitter.

It measures circulatory changes in brain areas according to metabolic processes and neuronal activity. But is this method really well suited to observe the release of happiness underlying dopamine? Michael Lippert of the Leibniz Institute for Neurobiology in Magdeburg and his colleagues have now studied this question

Barely Measurable Effects

For their study, they worked with genetically modified rats in which dopamine secretion in the brain is specifically controlled by light. can. In the experiment, rodents could reward themselves: if they pressed a lever, special light pulses would pull the cells releasing dopamine. "In doing so, an extreme reward stimulus is triggered," says Lippert colleague Marta Brocka.

Subsequently, the rats were examined in a tomographic tomograph for small animals. Is the previously induced liberation of the happiness hormone reliable? The result: "Despite the high reward value of stimulation, the measurable effects of dopamine were very low," reports Lippert. "This means that the release of dopamine underlying feelings of happiness is not directly measurable in MRI, so the essence of happiness remains invisible with this method."

Impact on the diagnosis

have other disorders badociated with changes in dopamine metabolism. In addition, the results are important for various research projects, as the scientists point out. Reward studies in animals and humans still badume a large influence of dopamine on signals measured in the brain.

"We must now abandon the hypothesis that the activity changes in the brain that we see as a result of the reward is direct Instead, we must use other methods to visualize the reward models of dopamine in the brain, "Lippert concludes. (Neuroimage, 2018, doi: 10.1016 / j.neuroimage.2018.04.059)