Temporal Lobe — Function, Anatomy and Damage

Where the temporal lobe sits

The temporal lobe lives mostly in the middle cranial fossa, a hollow in the floor of the skull just behind the eye socket. It sits below the lateral fissure, which separates it from the frontal and parietal lobes, with the frontal lobe in front of it and the occipital lobe behind. See how the four fit together on the lobes of the brain overview.

Three long ridges run front to back on the outer surface: the superior, middle and inferior temporal gyri. The underside carries the fusiform gyrus, which does a lot of the work of recognizing faces and objects. Fold the inner edge upwards and you reach the parahippocampal gyrus and the uncus, with the hippocampus and amygdala underneath.

Blood arrives from both circulations. Middle cerebral artery branches feed the temporal gyri, while the anterior choroidal artery supplies the uncus, the amygdala and the front of the parahippocampal gyrus.

Hearing and the auditory cortex

Primary auditory cortex is tucked out of sight on the upper surface of the superior temporal gyrus, inside the lateral fissure, on transverse ridges known as Heschl's gyri. It is laid out by pitch, like a piano keyboard smeared across the cortex, with low frequencies at one end and high at the other. That layout is inherited directly from the cochlea, which sorts sound by frequency before the signal ever reaches the brain.

The surrounding association cortex in the superior temporal gyrus takes that raw pitch map and finds patterns in it: speech sounds, a familiar voice, a car horn, a tune.

Sound from each ear reaches both hemispheres, so losing one auditory cortex does not make anyone deaf. It causes subtler trouble, like difficulty picking a voice out of a noisy room. Deafness in one ear points at the ear, the nerve or the brainstem instead.

Wernicke's area and understanding speech

Wernicke's area sits in the back of the superior temporal gyrus in the dominant hemisphere, usually the left, and it converts heard sounds into meaning. It is connected to Broca's area at the front of the brain, which is the comprehension-at-the-back, production-at-the-front loop that the classical language model is built on. There is more on the Wernicke's area region page.

Damage causes Wernicke aphasia, also called receptive aphasia. Speech keeps its normal rate and tone, so from across a room it sounds like a perfectly ordinary conversation. Up close, the words are wrong and the sentences make no sense. Comprehension is poor, and patients often do not realize anything is amiss, which is the sharpest contrast with the frustrated, effortful speech of Broca aphasia. The cause is usually an ischemic stroke, though infection and trauma do it too.

Memory: the hippocampus and amygdala

The hippocampus is about five centimeters long and curls along the floor of the temporal horn of the lateral ventricle. It got its name from its shape, which really does look like a seahorse in cross section. Anatomists split it into head, body and tail, and into three zones: dentate gyrus, hippocampus proper and subiculum. The hippocampus proper contains the CA fields, CA1 through CA4, with CA3 the largest and the main recipient of fibers from the dentate granule cells.

Input arrives from the entorhinal cortex next door. Output leaves along the fornix, a white matter bundle that arcs forward to the thalamus, hypothalamus and the rest of the limbic system. The hippocampus is involved in registering, storing and retrieving declarative memory, and bilateral damage leaves a person unable to lay down new memories at all.

The amygdala sits just in front of the hippocampal head. It is almond-shaped, which is exactly what its name means, and it is built from three groups of nuclei. Fear is the function it is best known for, but it also deals with other emotions, reward and social behavior. Bilateral amygdala damage can produce Klüver-Bucy syndrome, in which normal fear and inhibition drop away.

Temporal lobe epilepsy and other damage

Temporal lobe epilepsy is the most common focal epilepsy in adults, and scarring of the hippocampus, called hippocampal or mesial temporal sclerosis, is the usual culprit. Seizures often open with an aura the patient can describe: a rising feeling in the stomach, a wave of intense familiarity, a brief bad smell. Awareness then fades and automatisms appear, such as lip smacking or fumbling with the hands, followed by a period of confusion.

When medication fails, surgery is unusually effective here. Removing the affected section stops seizures in more than 80% of selected patients, and in one series 89% were either seizure free or had far fewer seizures afterwards. Hippocampectomy is the standard operation for sclerosis.

Other lesions leave their own fingerprints. Bilateral damage to the fusiform gyri makes familiar faces unrecognizable while vision itself stays fine. A lesion in the temporal white matter clips the optic radiation fibers looping through it and knocks out the upper outer quadrant of the opposite visual field, the defect students remember as “pie in the sky.” If field cuts are your weak spot, the visual field defects quiz drills them, and the parietal lobe page covers the fibers that take the lower route.

See the temporal lobe in 3D

The medial structures are almost impossible to picture from a side-on textbook diagram, so rotate a hemisphere on the 3D brain model and find the hippocampus curled inside the temporal horn. Then test recall in the brain lobes quiz and the brain regions quiz. Both are free, and you can retake them as often as you like.

Sources and further reading

A. Patel, G. M. N. R. Biso and J. B. Fowler, Neuroanatomy, Temporal Lobe, StatPearls, NCBI Bookshelf, updated July 24, 2023: https://www.ncbi.nlm.nih.gov/books/NBK519512/.

L. A. Fogwe, V. Reddy and F. B. Mesfin, Neuroanatomy, Hippocampus, StatPearls, NCBI Bookshelf, updated July 20, 2023: https://www.ncbi.nlm.nih.gov/books/NBK482171/.

Common questions