Auditory Cortex — Function, Location & Quiz

Primary auditory cortex is tucked into Heschl’s gyrus inside the lateral sulcus, so it is easy to point to the exposed superior temporal surface and miss the actual primary field. Its tonotopic map organizes sound frequency before auditory information separates into identity and location streams.

One-sided cortical injury rarely produces complete deafness because auditory pathways have bilateral representation. The more revealing deficits are difficulty localizing sound or recognizing what a heard sound means, while bilateral injury is required for cortical deafness.

Test this anatomy in the Brain Regions Quiz or open the interactive 3D brain model.

Location and anatomical map

Sound processing, pitch discrimination, auditory perception.

Atlas category: cortical. Brodmann areas or landmark: BA 41, 42 (primary auditory — Heschl's gyrus).

Functions

  • Processing sound frequency, intensity, timing
  • Tonotopic organization — frequency map like a piano keyboard
  • Sound localization (binaural cues)
  • Speech sound discrimination

Pathways and connections

  • MGN (medial geniculate nucleus of thalamus) → A1
  • A1 → Auditory 'what' stream (ventral, temporal — sound identity)
  • A1 → Auditory 'where' stream (dorsal, parietal — sound location)

Clinical relevance

  • Bilateral lesion → cortical deafness (rare — need both sides damaged)
  • Unilateral lesion → difficulty localizing sound, subtle deficits
  • Auditory agnosia — can hear but can't recognize sounds or music (amusia)

Key facts

  • Heschl's gyrus is buried in the lateral sulcus — not visible from outside
  • Tonotopic: low frequencies lateral, high frequencies medial
  • Planum temporale (behind Heschl's) is larger on the left — asymmetry linked to language lateralization

Exam tip

A1 is in Heschl's gyrus (hidden in the Sylvian fissure). Don't confuse with superior temporal gyrus (Wernicke's).

Common questions

Where is the primary auditory cortex?

It lies in Heschl’s transverse temporal gyrus, buried within the lateral sulcus. It corresponds mainly to Brodmann areas 41 and 42.

What is tonotopic organization?

Tonotopy is an ordered cortical map of sound frequency, with neighbouring neurons responding best to neighbouring frequencies, comparable to arranging notes along a keyboard.

Does one auditory cortex lesion cause deafness?

Usually not. A unilateral lesion causes subtler deficits such as impaired sound localization, while bilateral cortical damage is generally needed for cortical deafness.