Definition
The speech center in the conventional sense is not one, but two regions in the area of the cerebral cortex, i.e. in the central nervous system. The so-called motor speech center, also called the Broca’s area after its first descriptor, and the sensory speech center, also called the Wernicke’s area. Nowadays, however, it is becoming increasingly clear that not only these two regions in the brain are involved in speech production and processing, but that numerous other areas also play an important role in the complex processes of speech understanding and production. In this article, however, the two main language centers will be discussed.
Anatomy of the motor speech center
Synonym: Broca’s Area The motor speech center is located in the frontal lobe (frontal lobe) of the brain in the area of the inferior frontal gyrus. It therefore adjoins the temporal lobe (Lobus temporalis) at the bottom. In relation to the Brodman areas, it is located in areas 44 and 45.
The speech center is not present on both sides of the brain, but only on one hemisphere, the so-called dominant hemisphere. In most people, this is the left hemisphere of the brain. As a general rule, the dominant hemisphere for right-handed people is usually on the left side, for left-handed people it can be left or right.
Via the Fasciculus arcuatus, a strand of nerve fibers, the Broca area is connected to the Wernicke area, which is also essential for speech. From the Broca’s area, nerve fibers run in the direction of the motor cortex (motocortex), which is also located in the frontal lobe. This means that further switches are used to control muscles important for speech, especially those in the larynx and pharynx as well as the mimic muscles.
Function of the motor speech center
It is assumed that the Broca area is responsible for speech production. In particular, sentence structure and grammar seem to be processed and handled here. The language is formed here in wording and sentence structure.
However, contrary to earlier assumptions, the motor language center plays a role not only in language production but also in language comprehension. In the past, it was assumed that a clear distinction could be made between speech production in the Broca area and speech comprehension in the Wernicke area. This assumption is now considered questionable. Rather, language is created centrally through interaction of both centers and other smaller regions of the brain.
