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3|2012 Research in Jülich 19 cal patients, who are often lacking in certain abilities, synaesthetes have too many abilities, and yet they aren’t ill,” he says. Frauke Schröder – a trainee chem- istry and Spanish teacher – considers herself lucky too. “It only took me three days to learn the names of all the new students I teach at the moment. I also find it very easy to remember chemical formulae thanks to the colour associa- tions.” In the study, the researchers wanted to find out whether the anatomically modified regions of the brain communi- cate with each other to a greater extent. To do so, they investigated brain activity at rest in a total of 24 volunteers – twelve synaesthetes and twelve partici- pants who did not have this special gift. NO PEACE AND QUIET – EVEN AT REST The volunteers were instructed to re- lax, close their eyes and empty their minds. Dr. Anna Dovern, who examined all of the volunteers using functional magnetic resonance imaging, reports: “There is always something going on in the brain, even when you’re at rest. We wanted to find out which regions of the brain are coupled with one another when there are no external stimuli.” The Jülich scientists analysed the complex data sets together with a team from Munich headed by Dr. Valentin Riedl. The results were clear: in synaesthetes, coupling within individual networks was more pronounced, and coupling between net- works was moreover three times as in- tensive. The researchers also discovered that it is not only the regions responsible for colour perception and sensory link- ing that have a strong network; the re- gions of the brain that are responsible for auditory impressions are also in- volved. Frauke Schröder can also con- firm this first hand. When she reads a book, she sees the words as printed in black on white paper. However, if she reads the words out loud or hears them, Friday is coloured green, her own name takes on shades of yellow, and Sunday appears jet-black. “Perhaps it’s because once Sunday is over, the working week begins again,” she jokes. “I always had gymnastics on Wednesdays when I was small. Wednesday has been red for me for as long as I can remember,” says the trainee secondary school teacher. By reading the brain scans, the scien- tists were able to tell how strongly root- ed the sensory impressions were in each synaesthete. “There is a very clear cor- relation between the strength of the coupling and the consistency of synaes- thetic perception in each individual sy- naesthete,” says Weiss-Blankenhorn. This is because associations between colours and numbers vary in intensity from person to person. “This is also clearly reflected in the participants’ net- work structures,” Weiss-Blankenhorn is happy to report. But the researchers are still unable to answer the question of whether syn- aesthetes owe their extra abilities to a RESEARCH AT THE CENTRE | Synaesthesia particular network, or whether it is the abilities themselves that bring about the increased coupling. Anna Dovern says, “In order to find that out, we would have to systematically investi- gate synaesthetes from early childhood over a period of several years. That would be the only way to establish whether the extraordinary network structures are innate or whether the ex- tra aptitude leaves its traces in the brain over time, similar to the training effect with juggling.” NEW REHABILITATION POSSIBILITIES Neurologist Weiss-Blankenhorn con- siders the experiments to be extremely helpful for clinical practice. For the more scientists and doctors know about dif- ferent healthy networks in the resting brain, the better they can assess func- tional disorders in the brains of people suffering from serious illnesses. He ex- plains that modern imaging techniques are very effective in finding out which part of the brain has been affected in stroke patients. “But in practice, we fre- quently see that two patients with a le- sion in the same area of the brain ulti- mately display different deficits,” he adds. “The only explanation is that the network is arranged in a different way in each patient’s brain.” Medical scientists also want to understand how to stimu- late patients’ brains so that they can im- prove the network again. In future, they will be able to compensate for deficits caused by strokes, either partially or – under the right conditions – even fully. :: The perception of colour varies from one synaesthete to the next, yet remains con- sistent throughout their lives. A particular form of synaesthesia is when sounds produce colour impressions. The American composer Michael Torke, for example, possesses this extra aptitude. For Frauke Schröder, the days of the week are sorted by colour. Wednesday has always been red for her.