Superior temporal gyrus

Where is the superior temporal gyrus?

Its upper surface extends into the lateral fissure, where it forms the transverse temporal gyrus of Heschl. (Neuroscience Online, Overview of the Nervous System)

Its caudal part reaches up to the parietal cortex. (Neuroscience Online, Overview of the Nervous System)

What does the superior temporal gyrus do?

It holds the primary auditory cortex, which OpenStax A&P numbers as Brodmann’s areas 41 and 42 in the superior temporal lobe. (Neuroscience Online, Overview of the Nervous System; OpenStax A&P 2e, 13.2)

Ascending auditory fibers stop in the inferior colliculus of the midbrain and the medial geniculate body of the thalamus before they reach the cortex of this gyrus. (Neuroscience Online, Auditory System: Pathways and Reflexes)

The frequency map of the ear holds all the way to the cortex. In primary auditory cortex, low frequencies lie more lateral. (Neuroscience Online, Auditory System: Pathways and Reflexes)

Its caudal part forms part of Wernicke’s area, which processes auditory information and matters for understanding language. (Neuroscience Online, Overview of the Nervous System; OpenStax Psychology 2e, 3.4; StatPearls, Wernicke Area)

What lies around the superior temporal gyrus, and what does it connect to?

Above the cochlear nuclei, auditory fibers run to both sides of the brain, so damage to one side’s pathway or auditory cortex does not usually cause deafness in either ear. (Neuroscience Online, Auditory System: Pathways and Reflexes; OpenStax A&P 2e, 14.2)

A deep white matter tract, the arcuate fasciculus, links Wernicke’s area with Broca’s area in the inferior frontal gyrus. Diffusion tractography also shows an indirect route that relays through the inferior parietal cortex. (OpenStax A&P 2e, 16.2; Catani et al. 2005, Ann Neurol; StatPearls, Wernicke Area)

The insula lies deep inside the lateral fissure, covered by the parts of the frontal, parietal and temporal lobes next to the sulcus, the operculum. (Neuroscience Online, Overview of the Nervous System)

Where the sources differ

OpenStax A&P 2e gives two answers for where primary auditory cortex sits in Brodmann’s map. Section 13.2 puts it in areas 41 and 42 in the superior temporal lobe; section 16.2 calls area 22 the primary auditory cortex. StatPearls instead assigns area 22 to Wernicke’s area. (OpenStax A&P 2e, 13.2 and 16.2; StatPearls, Wernicke Area)

Sources place Wernicke’s area differently. StatPearls puts it in Brodmann area 22, the posterior superior temporal gyrus of the dominant hemisphere, and OpenStax Psychology 2e in the temporal lobe. Neuroscience Online’s overview says the caudal superior temporal gyrus forms part of it, but it also calls the inferior parietal gyrus Wernicke’s area. (StatPearls, Wernicke Area; OpenStax Psychology 2e, 3.4; Neuroscience Online, Overview of the Nervous System)