Network Level Decoding of Touch and Pain in the Spinal Cord

Lead researcher: Dr James Welsh

Touch and pain perception are crucial for human survival. Touch provides information about our interactions with the environment, while pain warns of impending danger. Normally these two sensations are kept separate within in the central nervous system. However, in certain pathologies the circuits that process these signals can overlap in the spinal cord dorsal horn (DH), causing the patient to experience pain at the slightest touch. This condition is known as touch-evoked pain, or allodynia.

To date, our understanding of the mechanisms underlying sensory coding in neural networks has focused on the discrete microcircuits that process touch and pain in the DH. While this effort has dramatically advanced our knowledge of DH microcircuitry, we still do not understand how dozens to hundreds of DH neurons act collectively to processes sensory information, as happens in real life sensory experience.

This project addresses the issue by using a special class of genetically encoded calcium indicators that are designed to form a permanent fluorescent tag in the DH neurons that we know are critical for touch and pain signals. These ‘tagged’ neurons can then be observed using a fluorescence microscope. Combining this process in ex vivo and in vivo mouse models, will allow us to measure network-wide DH activity during sensory input and determine how these networks code touch and pain. The use of an animal model of neuropathic pain will also determine how this network code is disrupted to allow touch to ‘evoke’ pain.

These insights will build a valuable framework for new methods in pain treatment including: better spinal cord stimulators to manipulate spinal sensory processing; new forms of neuro-prostheses to restore normal spinal cord signaling; and drugs that specifically manipulate spinal sensory processing to restore the normal separation of touch and pain signals.

The University of Newcastle acknowledges the traditional custodians of the lands within our footprint areas: Awabakal, Darkinjung, Biripai, Worimi, Wonnarua, and Eora Nations. We also pay respect to the wisdom of our Elders past and present.