The auditory cortex is on the upper side of each temporal lobe, in both hemispheres: parts of the superior temporal gyrus and of the transverse temporal (Heschl’s) gyri inside the lateral sulcus, roughly Brodmann areas 41 and 42 and partly 22. [1]
Lit: the whole superior temporal gyrus, on both sides. The area is part of this gyrus; its exact border is not drawn. The primary auditory cortex lies on the superior temporal gyrus where it extends into the lateral sulcus as the transverse temporal (Heschl’s) gyri; the model has no separate shape for those transverse gyri. [1][2]
The 3D brain needs JavaScript. The text below still says where the auditory cortex is and what it does.
Slice
Opens cut by a front (coronal) slice through the superior temporal gyrus, which holds the auditory cortex. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Takes part in: speech, hearing — see every part of each lit together.
Where it is
It lies on both sides, roughly at the upper sides of the temporal lobes, within the lateral sulcus, and is made of parts of the transverse temporal gyri and the superior temporal gyrus. [1]
The primary auditory cortex lies in the superior temporal gyrus and extends into the lateral sulcus and the transverse temporal gyri, also called Heschl’s gyri. [1]
The transverse temporal gyri are buried in the lateral sulcus and, unlike the other temporal gyri, run mediolaterally, toward the centre of the brain; they sit above the planum temporale, separated from it by Heschl’s sulcus. [3]
Their number varies from person to person, in both the left and the right hemisphere: one gyrus gives an omega shape, two with a sulcus between them a heart shape. [3]
It has three parts: the core (the primary auditory cortex, A1) in the middle, the belt (secondary, A2) and the parabelt (tertiary, A3) on the outside. [1]
What it does
The transverse temporal gyri are the first parts of the cortex to process incoming sound. [3]
The core keeps tonotopy, an orderly map of sound frequency: neurons at one end respond best to low frequencies, in the same order as the cochlea, where low frequencies map to its apex and high ones to its base. [1]
It identifies and separates “auditory objects”, and its neurons respond to pitch. [1]
Both sides work on sound: the right auditory cortex has long been shown to be more sensitive to tonality, the left to small sequential differences in sound. [1]
Connections
The primary auditory cortex receives direct input from the medial geniculate nucleus of the thalamus. [1]
Auditory fields are interconnected within the same hemisphere and with the opposite one. [1]
Wernicke’s area, behind it on the same gyrus, receives input from the auditory cortex. [4]
Other names
Brodmann areas 41 and 42, and partly area 22; the primary auditory cortex is also called A1. [1]
Heschl’s gyri, named after Richard L. Heschl, are the transverse temporal gyri, Brodmann areas 41 and 42. [3]
Size
The model has no shape for the auditory cortex itself, so it is not measured here. The whole left superior temporal gyrus that holds it measures about 106 mm front to back, 49 mm top to bottom and 43 mm side to side on this model (the box it fits in, not its volume). [2]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.