Decoding Neuropathic Pain in the Central Nervous System Through the Peri-Stimulus Histogram Method

Neuropathic pain develops as a result of damage to the peripheral or central nervous system from lesions or other forms of dysfunction. In a clinical setting, neuropathic pain is difficult to treat because the underlying mechanisms and pathophysiology are not well known. In order to investigate the connection between neuropathic pain and motor cortex encoding, rats with spared nerve injuries (SNI) were utilized as models. Using active stimulation methods, somatosensory data from both lesioned and sham paws was collected via two microarray electrodes in the hindlimb sensory motor cortices. The peri-stimulus time histogram (PSTH) method was employed for data classification. Compared to the sham group, the SNI group exhibited significant mean neuron response increases in the somatosensory cortex contralateral to the lesion site when exposed to a noxious surface. In addition, the uninjured limb also showed increased mean neuron responses in ipsilateral and contralateral sensorimotor cortices. These results support the idea that neuropathic pain is encoded in the central nervous system and not restricted to the periphery. Further exploration of these central nervous system mechanisms is required in order to develop a neurocomputational model of neuropathic pain.