Unmyelinated C fibers and lightly myelinated A-beta fibers (small nociceptive fibers, which conduct pain) Nociceptive Fibers (peripheral pain receptors) They send this information to second-order neurons located in the spinal cord, mainly in the dorsal horn (central pathways), which are then transmitted via projection neurons to the brainstem (integrative neurons). First, nociceptors receive signals of noxious temperature, chemical, or mechanical stimuli (peripheral neurons). The interrelation between these three systems is responsible for the perceived sensation of pain and the responses associated with it. Multiple pain systems are responsible for the sensation of pain these systems are composed of integrative neuronal sets (conduct excitatory or inhibitory signals on the nociceptors). In other words, stimulation of the touch and vibration nerves “closes the gate” on ascending pain impulses that carry noxious pain stimuli cephalad. This interruption is facilitated by the common nerve synapse location in the substantia gelatinosa of the dorsal horn.

In summary, they posed that pain impulses provoked in the periphery, which are carried by C fibers and A-delta fibers, could be interrupted by stimulating larger A-beta fibers. Neurostimulation modalities arose as a response to treating the gate control theory of pain by Melzack and Wall. A similar principle utilizes the central nervous system and the peripheral nervous system stimulation in deep/cortical brain stimulation and peripheral nerve stimulation, respectively. Presently, neuromodulation involves the implantation of leads in the epidural space. Initially, this technique applied pulsed energy in the intrathecal space.

Spinal cord stimulation uses pulsed electrical energy near the spinal cord to manage pain.

Dorsal column spinal cord stimulation