Wernicke's area

Where is Wernicke's area located?

Speech centers in the vast majority of people (about 95%) are lateralized and located in the left (dominant) hemisphere (on the side opposite to the dominant right hand). Wernicke's area is spatially separated from the primary sensory and motor areas of the cortex.

• Superior temporal gyrus — the area occupies its posterior half (Brodmann area 22, specifically 22b).
• Inferior part of the parietal lobe — the area includes the adjacent angular gyrus (gyrus angularis) and supramarginal gyrus (Brodmann areas 39, 40).
• Planum temporale region — an anatomical area whose size correlates with hemisphere dominance.

The most important speech regions are located around the lateral sulcus (Sylvian fissure).

How does the sensory speech center work?

Wernicke's area is responsible for the impressive component of speech — the ability to understand other people's speech and accurately perceive one's own.

The mechanism of action is based on the analysis of incoming information:

1. The primary auditory cortex (transverse temporal gyri of Heschl) perceives sounds and transmits impulses to Wernicke's area.
2. The brain differentiates words from non-verbal information.
3. Information is decoded in Wernicke's area: heard sounds are analyzed, classified as words, and the semantic structure of speech is created.

In addition to auditory information, the area receives afferent impulses from secondary visual areas (which forms the basis for reading and writing) and the cortical part of the tactile analyzer (for Braille reading).

Connections with other structures

To produce spoken language, it is necessary to transmit the formed semantic meaning to the motor centers.

• Arcuate fasciculus (fasciculus arcuatus) — an association pathway of arcuate fibers connecting Wernicke's sensory center and Broca's motor center. Through it, excitation carrying information about the goal of speech is transmitted for the further formation of the vocalization program.

Blood supply

Wernicke's area is supplied with blood from the basin of the middle cerebral artery (MCA). The cortex in the region of the angular and supramarginal gyri receives blood supply from the angular and posterior parietal arteries.

Clinical significance and symptoms of lesion

When Wernicke's area is damaged (e.g., in a cerebral infarction in the MCA basin), sensory aphasia (also called fluent aphasia) develops.

Key clinical manifestations:

• Impairment of phonemic hearing: the patient loses the ability to distinguish phonemes (meaning-forming combinations of letters), which disrupts the comprehension of spoken language.
• Alteration of own speech: speech remains effortless, rapid (fluent), and phonetically correct, but becomes meaningless.
• Associated symptoms: with bilateral lesions of the temporal lobes, euphoria and auditory hallucinations may be observed.

MRI findings in infarction: On diffusion-weighted imaging (DWI) and FLAIR images, the infarction zone is visualized as a hyperintense area. On T2-weighted imaging, the lesion is located above the lateral sulcus. If the lesion extends deep to the wall of the lateral ventricle, the optic radiation may be involved, causing right homonymous hemianopsia — loss of the right half of the visual field. When the precentral region is involved, hemiparesis develops.

Class and exam questions

What else to study on this topic

• Broca's area
• Arcuate fasciculus
• Primary auditory cortex (Heschl's gyri)
• Aphasias (motor and sensory)
• Angular gyrus

Other topics in the "Anatomical Structures" section

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