Cortical area · one in each half of the brain
Primary auditory cortex
Also called Heschl's gyrus, A1, Brodmann area 41
The first cortical stop for sound, laid out by pitch like piano keys.
Hidden inside the deep groove on the side of the brain, this small ridge is where sound first reaches the cortex. It is laid out by pitch: low notes activate one end and high notes the other, just like keys on a piano. From here, sound is passed to neighboring areas that recognize speech, music and voices.
Where it is
On the upper surface of the temporal lobe, deep inside the lateral sulcus. You cannot see it from the outside unless you gently pull the lobes apart. It lies roughly above your ear.
What it does
Receiving sound
It is the first part of the cortex to get sound information coming up from the ears.
Sorting by pitch
Different spots respond to different pitches, from deep bass to high whistles.
Timing and loudness
It tracks how loud a sound is and how it changes over time, which helps with rhythm and speech.
Hearing from both ears
Each side gets signals from both ears, with a little more from the ear on the opposite side.
Think of it as a piano played in reverse: instead of pressing keys to make notes, incoming notes light up their own keys.
Works with
- Medial geniculate nucleusThis relay station in the thalamus is the last stop for sound signals before they reach this gyrus.
- Acoustic radiationThis fan of fibers carries sound signals from the thalamus to this gyrus.
- Inferior colliculusA hearing hub in the midbrain that processes sound earlier on its way up from the ear.
- Vestibulocochlear nerve (VIII)Sound starts its journey in the inner ear and travels into the brain along this nerve.
- Superior temporal gyrusIt hands sound on to the areas around it, which recognize speech, music and voices.
When it goes wrong
Cortical deafness
Because each side hears from both ears, damage on one side usually causes only subtle problems. Rare damage on both sides can cause deep trouble with hearing even though the ears work.
Tinnitus
Ringing in the ears often starts with hearing loss in the ear, but changes in the brain's hearing areas seem to help keep the phantom sound going.
For learning only, not medical advice. If you have a health concern, talk to a doctor.
Surprising facts
- Some people have two Heschl's gyri on one side instead of one. It is a normal variation.
- Studies have found that professional musicians tend to have a larger Heschl's gyrus than non-musicians.
- Sound reaches this area within a few hundredths of a second after hitting your ear.
By the numbers
Where the name comes from
"Transverse" means "lying across". Unlike the other temporal ridges, which run front to back, this one runs crosswise, pointing inward. It is also called Heschl's gyrus after anatomist Richard Heschl, who described it in Vienna in the 1870s.
Learn it in a lesson
- LanguageHearing, understanding, speaking, reading. A short guided lesson in 3D.
- Hearing and balanceFrom the inner ear to the cortex. A short guided lesson in 3D.
Quick quiz
3 questions. Your answers are saved and come back in your daily review.
Which of these is a job of the primary auditory cortex?
Show the answer
Receiving sound. It is the first part of the cortex to get sound information coming up from the ears.
Receiving sound. It is the first part of the cortex to get sound information coming up from the ears.
The primary auditory cortex is part of which larger structure?
Show the answer
Temporal lobe. It belongs to the temporal lobe.
Temporal lobe. It belongs to the temporal lobe.
Which part fits this description? "Like a piano played in reverse: instead of pressing keys to make notes, incoming notes light up their own keys."
Show the answer
Primary auditory cortex. It is the primary auditory cortex. The first cortical stop for sound, laid out by pitch like piano keys.
Primary auditory cortex. It is the primary auditory cortex. The first cortical stop for sound, laid out by pitch like piano keys.
These parts now come back in your daily review, just before you would forget them.
Practice it and its neighbors in 3DSources
- Heschl's gyrus, Radiopaedia
- Neuroanatomy, Cortical Primary Auditory Area (Archived), StatPearls, NCBI Bookshelf
- How Does Acoustic Information Enter the Brain?, OpenStax, Introduction to Behavioral Neuroscience
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Explore the primary auditory cortex in 3D
Turn it around, zoom inside and see how it connects to the rest of the brain, then test yourself with quick quizzes.
Open it in 3D