Superior temporal gyrus
Gyrus temporalis superior
cortical
The uppermost gyrus of the temporal lobe, bounded above by the lateral fissure and below by the superior temporal sulcus. The dorsal surface of the gyrus, hidden in the lateral fissure, carries Heschl's transverse gyri (primary auditory cortex) and the planum temporale (posterior to Heschl's). The lateral convexity carries Brodmann area 22 along its length.
The posterior third of the left superior temporal gyrus, together with the adjacent supramarginal gyrus, comprises Wernicke's territory, the classical receptive language area. Damage here produces fluent (Wernicke's) aphasia with severely impaired comprehension and frequent semantic paraphasias, often with preserved articulation and prosody. The anterior superior temporal gyrus contributes to semantic processing more broadly, including object naming and category-specific knowledge.
The dorsal-stream language pathway from Wernicke's territory to Broca's territory runs through the arcuate fasciculus; the ventral semantic stream connects to inferior frontal cortex through the inferior fronto-occipital fasciculus and uncinate fasciculus. Modern dual-stream models (Hickok-Poeppel) frame the dorsal pathway as supporting sound-to-articulation mapping and the ventral pathway as supporting sound-to-meaning mapping.
language
Carl Wernicke’s 1874 monograph, written when he was 26, proposed a distinct posterior superior-temporal language area complementary to Broca’s frontal one. The dissociation between expressive (Broca’s) and receptive (Wernicke’s) aphasia became the founding distinction of modern aphasiology and has held up in broad strokes over a century and a half, although the exact cortical boundaries of “Wernicke’s area” have been continuously revised by lesion studies and modern imaging.
The most recent reviews (Binder 2017, Hagoort 2014) argue that the classical Wernicke’s-area boundary, drawn around posterior BA 22, is both too anatomically narrow and too functionally specific to capture the cortical substrate of comprehension. Lesions producing classical Wernicke’s aphasia almost always involve the underlying white matter (arcuate fasciculus, middle longitudinal fasciculus) and surrounding inferior parietal and middle temporal cortex; selective damage to posterior STG alone produces a milder syndrome.
The right superior temporal gyrus has a complementary specialisation for prosody (the emotional and prosodic content of speech) and for non-verbal sound recognition. Bilateral involvement of the dorsal STG including Heschl’s gyrus produces pure word deafness (see heschl-gyrus-left for details) and in rare cases cortical deafness.