Read aloud How does pleasure arise in the brain? As before, the processes that trigger joy in the brain are not explored in detail. A key role is played by certain messengers, the opioids, which include the endorphins. However, many brain regions react to the opioids. Which of them are crucial for the sense of pleasure, the neuroscientists can not say so far with certainty. Two areas seem to be fundamental, at least for the enjoyment of sweets and fragrances. "Joy, beautiful divine spark" - what Schiller praised in his ode as a divine gift, can be described from the perspective of modern brain research quite sober as a biochemical process in the brain. The exact processes that create happiness and happiness in the brain, however, are still a mystery to neuroscientists. Nobody can say exactly where the feelings of happiness sit, explains Professor Borwin Bandelow from the Department of Psychiatry and Psychotherapy at the University of Göttingen to ddp.

Joy has countless occasions and is at the same time difficult to reach. Where do the scientists go to explore them? "There are two of the basic needs: hunger and sex, " says Bandelow. When they are breastfed, joy arises. For the most part, brain research is based on such tangible pleasures and examines the processes that take place in the brain.

In the sixties, the messenger substance dopamine was regarded as the chemical basis of pleasure. It stimulates the nerve cells of the so-called reward center in the brain. Computer tomography shows that this center is always active when people enjoy something - be it good food, sex, music or drugs.

However, some attempts contradict the image of dopamine as a source of pleasure. Instead, they show it as the source of desire. Kent Berridge of the University of Michigan at Ann Arbor, for example, examined rats in which he had destroyed the receptors for dopamine. Although they did not eat on their own, if they were forced to do so, they still enjoyed sweets. They still liked sweets but did not want them anymore, Berridge concluded. Similarly, tests by Jaap Panksepp of Ohio Bowling Green State University with people whose dopamine receptors were blocked by a drug. display

Dopamine thus creates a desire and thus signals the body a need. Other messengers provide the joy of fulfilling this desire: the opioids, which include endorphins, but also drugs like heroin. If the activity of the opioids is blocked in the brain, food does not taste so good, although the feeling of hunger does not disappear.

The receptors for opioids are distributed throughout the brain. However, two regions seem to be of particular relevance to cognitive ability: the so-called ventral pallidum near the reward center and the orbitofrontal cortex (OFC) behind the eyes. Opioids injected directly into the ventral pallidum increase the enjoyment of sweet things. This joy disappears when the ventral pallidum is destroyed.

Experiments by Edmund Rolls of the University of Oxford show how pleasure arises in the OFC in response to a sensory stimulus. Rolls had his subjects each inhale three pleasant and three unpleasant odors. Meanwhile, he observed her brain activity using magnetic resonance imaging. When smelling, the sensory cortex first became active, depending on the intensity of the odor, it reacted more or less strongly. These reactions were independent of whether the subjects perceived pleasant smell or unpleasant odor. Then the signal reached the OFC. Here, the unpleasant odors activated areas other than the pleasant ones. The better or worse the subjects liked a smell, the stronger this reaction was. So when a signal goes through the OFC, it gets a positive or negative sign.

The pleasure of fragrances, as Rolls has studied them, is innate, as is the many sensory impressions. It gets more complicated with the acoustic perception. "Five-tone music, for example Scottish or Chinese music, like all primitive peoples, " explains Bandelow. And animals are also susceptible to it: "Cows, who get played simple music, give more milk". So she is also innate. Jazz music, on the other hand, opens up only when one enters a culture. The enjoyment of more complex soundscapes, like the enjoyment of other abstract things, must first be learned.

But even with the learned joys, the underlying processes in the brain are probably quite similar to sniffing a rose. They, too, seem to be linked to the activity of the OFC. Presumably every kind of joy there is connected to a very special group of nerve cells: some react to sweets, others to music, others to smells.

Katharina Vogelmann

© science.de

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