All parts of the brain › Touch

What part of the brain feels touch, temperature and pain?

Mainly the postcentral gyrus, the strip of cortex just behind the central sulcus that holds the primary somatosensory cortex: a map of the opposite side of the body, where touch, pressure, vibration, temperature and pain are registered and placed on the body. The signals reach it by two routes that both stop in the thalamus first: fine touch, vibration and limb position travel up the dorsal columns and medial lemniscus, while pain, temperature and crude touch travel up the spinothalamic tract. [1][2][3][4]

The 3D brain needs JavaScript. The list of parts still says what each one does for touch, temperature and pain.

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Touch: 6 parts lit

Postcentral gyrus, thalamus, parietal lobe, insula, cingulate gyrus and brainstem. Tap one to see where it is and what it does.

The parts and their roles

Holds the primary somatosensory cortex (Brodmann areas 3, 1 and 2), laid out as a body map in which the lips, face and hands take up far more cortex than the back or legs. [1][5] Where is the postcentral gyrus?
Its ventral posterolateral nucleus relays touch, pain and temperature from the body, and its ventral posteromedial nucleus the same from the face, on to the somatosensory cortex. [6][7] Where is the thalamus?
Beyond the primary strip, its association areas, including the superior parietal lobule, combine touch with body position and vision, which lets you tell two nearby points apart or recognise a letter traced on the skin by touch alone. [8][9] Where is the parietal lobe?
Its posterior part receives temperature and pain signals relayed from the thalamus and is a main cortical area for interoception, the sense of the body’s internal state. [10][11] Where is the insula?
Its front part, the anterior cingulate cortex, registers pain as it is felt: in brain-imaging studies its activity rises with pain intensity, and it is linked to the emotional, unpleasant side of a pain. [12][13] Where is the cingulate gyrus?
In the medulla the gracile and cuneate nuclei receive fine-touch fibres from the dorsal columns; their output crosses over as the medial lemniscus and climbs through the pons and midbrain to the thalamus, beside the spinothalamic tract. [3][4] Where is the brainstem?

How they work together

Each kind of feeling starts at its own receptors in the skin: Meissner corpuscles for light touch, Pacinian corpuscles for vibration, Merkel endings for pressure and texture, Ruffini endings for stretch, and free nerve endings for temperature (thermoreceptors) and for pain (nociceptors). [14][15][16]
The two routes cross to the other side at different heights. Fine-touch fibres climb the spinal cord on the same side and cross in the medulla; pain and temperature fibres cross within a segment or two of entering the spinal cord. Both end up on the opposite side, so the left postcentral gyrus feels the right side of the body. [3][4][9]
A pinprick is often felt twice: a quick, sharp first pain carried by thin myelinated A-delta fibres, then a slower, duller second pain carried by unmyelinated C fibres, which conduct more slowly. [15][17]
The body map was charted by Wilder Penfield by gently stimulating the exposed cortex of awake people, who reported where on the body they felt it. Its size follows how densely an area is supplied with receptors, which is why fingertips can tell two points apart that the back feels as one. [5][18]
Honest limit: the relay nuclei of the thalamus, the gracile and cuneate nuclei and the posterior insula have no separate pieces on this model, so the whole thalamus, brainstem and insula light; the parietal lobe piece covers more than its touch areas; and the skin receptors and the spinal cord, where much of the sorting happens, are outside the brain model. There is no single pain centre: several of these areas work together each time. [13][19]

Sources

Facts describe anatomy and normal function only. A part lit here takes part in touch, temperature and 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.