Central Sensitization Mechanisms in Pain Perception

Central sensitization describes the process by which neurons in the central nervous system become hyperresponsive following persistent or intense noxious input. This phenomenon relies on synaptic plasticity within the dorsal horn of the spinal cord and brainstem nuclei, manifesting as both homotopic and heterotopic amplification of pain signals. Mechanisms include reduced inhibitory neurotransmission, enhanced excitatory transmission and the recruitment of long-term potentiation-like processes at nociceptive synapses. Microglial and astrocytic activation further sustains a proinflammatory milieu that facilitates neuronal excitability. Changes in descending modulatory pathways can tip the balance towards facilitation, reinforcing pain persistence. Clinically, central sensitization underlies secondary hyperalgesia, allodynia and spread of pain beyond the original injury site. An improved understanding of the molecular and network-level drivers of sensitization is pivotal for the development of targeted analgesic strategies that restore inhibitory control or interrupt maladaptive plasticity.

Research from Nature Portfolio

Recent work has demonstrated that topical capsaicin application evokes a sustained increase in the N13 component of the somatosensory evoked potential, reflecting heightened dorsal horn excitability. This neurophysiological marker paralleled the development of secondary mechanical hyperalgesia and was prevented by pre-treatment with pregabalin, suggesting its value as a biomarker for central sensitization and for assessing the efficacy of spinally acting analgesics. Another study explored whether mechanical conditioning that induces secondary hyperalgesia also biases perception of non-nociceptive stimuli. Despite robust pinprick sensitization, there was no prioritisation of vibrotactile or visual inputs in the sensitized region, indicating that central sensitization as currently defined does not extend to attentional or multisensory amplification.

Central Sensitization Mechanisms in Pain Perception publication trend

The graph below shows the total number of articles in central sensitization mechanisms in pain perception across all publications each year (not limited to Nature Index journals).

Technical terms

Central sensitization: A state of amplified neuronal responsiveness in the spinal cord and brainstem following repeated or intense noxious input.

Secondary hyperalgesia: Heightened pain sensitivity in tissue surrounding an injured area, arising from central nervous system plasticity.

Long-term potentiation-like plasticity: Persistent strengthening of synaptic transmission, analogous to memory mechanisms, occurring at nociceptive synapses.

Dorsal horn neurons: Spinal cord neurons that receive primary afferent input and relay nociceptive signals to higher centres.

Descending modulatory pathways: Brainstem networks that exert inhibitory or facilitatory control over spinal nociceptive processing.

References

1. Modulation of the N13 component of the somatosensory evoked potentials in an experimental model of central sensitization in humans. Scientific Reports (2021).
2. No perceptual prioritization of non-nociceptive vibrotactile and visual stimuli presented on a sensitized body part. Scientific Reports (2018).
3. A back-translational study of descending interactions with the induction of hyperalgesia by high-frequency electrical stimulation in rats and humans. Pain (2024).
4. How different experimental models of secondary hyperalgesia change the nociceptive flexion reflex. Clinical Neurophysiology (2021).
5. Perceptual correlates of homosynaptic long-term potentiation in human nociceptive pathways: a replication study. Royal Society Open Science (2021).