Language center of the brain was misplaced

Wernicke area is three centimeters further forward than previously thought

The active area in the temporal lobe during the processing of words shows the location of the Wernicke area © DeWitt and Rauschecker / PNAS
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The language center of our brain is located elsewhere than previously thought: It is not behind, but in front of the area of ​​the cerebral cortex, in which we process what we hear. This has now been proven by American researchers. The new position of the so-called Wernicke area differs by three centimeters from the previously mapped - in terms of brain architecture and function that was miles away. "This means that the textbooks now have to be rewritten, " says Josef Rauschecker, one of the authors of the Georgetown University Medical Center in Washington DC. Almost all popular graphic representations are wrong. The researchers report in the journal "Proceedings of the National Academy of Sciences".

As early as 1874, the German neurologist Carl Wernicke discovered that an area in the posterior temporal lobe of the brain is responsible for understanding speech. This position of the Wernicke area has remained the common doctrine until today. This did not change when in the 1990s modern imaging techniques increasingly provided evidence of a situation further ahead. "The majority of researchers have shied away from overturning a doctrine established over a century based on these images, " says first author Iain DeWitt. But that has now changed: "It is now no longer tenable to overlook or reject evidence that supports the central role of the anterior and middle temporal lobe in understanding spoken language, " says the researcher.

Important for treatment of stroke patients

Among other things, the new finding is important for the treatment of patients with strokes or brain damage. For if the Wernicke center is injured, those affected often no longer understand the content of spoken words and make meaningless sentences. "If a patient can not speak or does not understand speech, we now have a better indication of where the brain is damaged, " says Rauschecker.

But for the question of how the language once developed, the new knowledge is important, say the researchers. Because the new position of the Wernicke area exactly matches that of a similar center recently discovered in monkeys. This proves that the brain architecture in monkeys and humans is also more similar in terms of communication than often assumed.

800 coordinates from 115 studies evaluated

For their study, the researchers had compiled 800 coordinates for the location of the language center from 115 studies. In most studies, scientists had recorded where the brain was particularly active when their subjects had to complete language comprehension tasks. Using a statistical procedure, Rauschecker and DeWitt analyzed for which positions there were most similarities. In addition, they also carried out their own measurements. display

The result is clearly in favor of a position in the anterior part of the so-called superior temporal gyrus, the upper of three branches in the temporal lobe. This clearly puts the Wernicke area in front of the general bark of the brain and not behind it. (PNAS, 2012; doi: 10.1073 / pnas.1113427109)

(PNAS, 31.01.2012 - NPO)