What is nociception?

Nociception is the neural process of encoding noxious stimuli. It is caused by mechanical, chemical and thermal stimuli that threaten or damage tissues, which activates nociceptors (receptors in skin and deep tissues that are sensitive to potentially noxious stimuli).

Activity induced in the nociceptor and nociceptive pathways is not pain. Sufficient activation of nociceptors generates a signal to the spinal cord, which is then modulated. Modulation (via sensitisation and descending inhibition) alters the strength of the neural signal prior to inputting it to the brain. The brain interprets this modulated signal and pain may be perceived; see What is pain?

Note: Activity induced in the nociceptor and nociceptive pathways is not pain.

At the spinal cord, nociceptive signals may also provoke a reflex response (eg a motor response causing a withdrawal reflex from the stimuli).