The left-wingers

Brain researchers plan an unusual experiment

It seems sheer unbelievable: the direction of rotation of the head hair and the speech processing of a person in the brain are connected. And to investigate this connection in more detail, brain researchers at the University Clinic for Epileptology in Bonn are looking for test subjects whose hair rotates counterclockwise at the main vertebra (the vertebra at the top of the head).

But so "hair-raising", as it sounds, the matter is not. The American geneticist Amar J. S. Klar from the National Cancer Institute, Frederick/Maryland has proven that the agility of a person and the direction of rotation of the main vertebra on the head are determined by a single gene. But not every left-handed person’s main vortex rotates to the left – handiness and main vortex are not fixed to each other, and chance also has a hand in this. Since humans are endowed with a double set of chromosomes, they have either two different expressions of a gene or two identical ones.

Photo: Christian Hoppe

For the handiness this means casually said: either right or coincidence. There are three possible combinations: Either both alleles point to the right, or one points to the right, one points to chance, or both point to chance. If even one thing points to the right, then everything probably goes to the right, i.e. you become a right-winger and your hair also turns to the right. If both point to chance, then both can develop by chance. The result is the following picture: if you meet people who are left-handed, in half of the cases they are also left-handed; whereas normally the proportion of left-handed people in the population is less than 10 percent.

But the sidedness of a human being goes even further: it is a fact that usually the left half of a human being’s brain does most of the work in understanding and speaking. Here, too, there is a connection with handedness: for it is often the case with left-handed hikers that the right half of the brain dominates in speech. The neuroscientists in Bonn now want to take the whole thing a bit further. They want to find out if there is a connection between the direction of the whirl of the main hair and the half of the brain where language processing takes place. With functional magnetic resonance imaging this is possible in an inexpensive way.

Men between 20 and 40 years of age, whose main vertebrae clearly point to the left, are therefore being sought. Unfortunately, women are not eligible as test subjects. The brain researchers have learned that the spatial organization of language in the brain of women is subject to hormonal fluctuations that are related to the menstrual cycle. Depending on the menstrual cycle, women have phases in which language activation takes place in the left part of the brain and phases in which it is the right half of the brain. In the case of female test participants, the cycle status always had to be taken into account, which made things unnecessarily complicated.

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