All parts of the brain › Functions › Pain

What part of the brain processes pain?

Pain is processed in several places at once, not in one pain centre. [1][2][3][4]

The thalamus, the postcentral gyrus, the insula, the cingulate gyrus, the midbrain and the prefrontal cortex lit in red on a 3D model of the brain, seen from the front left and above

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Lit: whole parts; region borders not drawn.

Slice

All 6 parts are lit together. Drag to turn, pinch or scroll to zoom, tap a part on the brain or a name in the list to focus it; .

Signals from pain receptors (nociceptors) climb the spinothalamic tract to the thalamus, which passes them on to the cortex: the primary and secondary somatosensory cortex on the postcentral gyrus and its operculum work out where the pain is and how strong, while the insula and the anterior cingulate cortex carry how unpleasant it feels. The periaqueductal grey in the midbrain is the main control centre for turning incoming pain down. [1][2][3][4]

The anterior cingulate cortex is a region on a lit gyrus, not a separate shape. The 3D model draws only whole gyri, so the gyrus that holds each area is lit; the area’s exact border is not drawn.

The secondary somatosensory cortex is a region on the postcentral gyrus, not a separate shape. The 3D model has no shape for it, so the whole postcentral gyrus is lit; the region’s exact border is not drawn.

Pain: 6 parts lit

Thalamus, postcentral gyrus, insula, cingulate gyrus, midbrain and prefrontal cortex. Tap one to see where it is and what it does.

The parts and their roles

The fast, sharp pain signal of the spinothalamic tract ends in its ventral posterolateral nucleus, which relays it to the somatosensory cortex; in a PET study its activity on both sides rose with how intense a heat pain felt. [1][5] Where is the thalamus?
Holds the primary somatosensory cortex, which places a pain on the body map; when hypnotic suggestion made the same heat feel more or less intense, its activity changed with the felt intensity. [2][6] Where is the somatosensory cortex (postcentral gyrus)?
Pain-related activity spreads from the thalamus to the insula, thought to carry the feeling that tells pain apart from other body feelings; its activity on both sides rose with pain intensity. [1][5] Where is the insula?
Holds the anterior cingulate cortex, which tracks how unpleasant a pain is: when hypnosis made the same heat feel more or less unpleasant but not more intense, its activity changed while the primary somatosensory cortex’s did not. [7][1] Where is the cingulate gyrus?
Holds the periaqueductal grey, the main control centre of the brain’s own pain damping: electrical stimulation at its edge in rats stopped their responses to painful stimulation while they could still move normally. [3][8] Where is the midbrain?
Its dorsolateral prefrontal cortex may hold pain back from the top down: in 14 healthy men, the more active it was while heat was laid on skin made sensitive with capsaicin, the hot part of chilli, the less intense and unpleasant they rated it. [9] Where is the prefrontal cortex?

Named areas on the lit gyri

Anterior cingulate cortex, on the : On the cingulate gyrus; its activity followed how unpleasant a heat pain felt, not how intense. [7]
The secondary somatosensory cortex, on the : Also called S2; it lies in the parietal operculum on the ceiling of the lateral sulcus, part of the lid that lies on the postcentral gyrus. Imaging finds it active to pain as well as to light touch, and its activity on both sides rose with pain intensity. [10][11][5]

How they work together

How it gets there: pain fibres enter the spinal cord, cross to the other side through the anterior white commissure and climb the spinothalamic tract to the thalamus, so the left half of the brain feels pain from the right side of the body. [1][12]
Pain is defined as an unpleasant sensory and emotional experience tied to actual or potential tissue damage, which is why it lights both sensory areas (the somatosensory cortex) and emotional ones (the insula and the anterior cingulate cortex). [1]
Two sides of one pain: in two PET studies by the same group, changing only how intense a heat felt moved activity in the primary somatosensory cortex, while changing only how unpleasant it felt moved the anterior cingulate cortex. [6][7]
A pattern, not a spot: across four studies of 114 people, a brain-scan pattern spanning the thalamus, insula, secondary somatosensory cortex, anterior cingulate cortex and periaqueductal grey told painful heat from mere warmth with 94% or better sensitivity and specificity in its first study. [4]
The brain turns pain down by itself: the periaqueductal grey signals the raphe nuclei, whose serotonin fibres run down to the dorsal horn of the spinal cord and damp pain signals there before they climb on. [3][2]
Honest limit: these are networks seen in imaging and animal work, not single centres; the scans give brief heat to small groups of healthy volunteers (ten in one PET study, 14 in another), the stimulation work on the periaqueductal grey was done in rats, and the ventral posterolateral nucleus, S2, the anterior cingulate cortex, the dorsolateral prefrontal cortex and the periaqueductal grey have no separate shapes on this model, so whole parts are lit, not exact borders. [6][9][8][13]

Pain shares the thalamus and postcentral gyrus with touch, but fine touch climbs its own route, the dorsal columns, while pain and temperature climb the spinothalamic tract; the touch page lights the whole body-feeling network. [14][12] What part of the brain feels touch, temperature and pain?

Itch travels the same road as pain, its unmyelinated fibres using the same nerve bundle and spinothalamic tract, but pain sets off a reflex to pull away and itch a scratch reflex. [15] What part of the brain feels an itch?

Sources

Facts describe anatomy and normal function only. A part lit here takes part in feeling pain; it does not do it alone, and it does other jobs too. The 3D model is the adult male BodyParts3D brain (credits and licence); on it the brainstem includes the midbrain, pons and medulla, so lighting the brainstem lights all three.