Oral Presentation 18th International Congress on Photobiology 2024

Advances in neurosciences are largely driven by technology.  The combination of optogenetics with modern genetic and fiberoptics tools have allowed researchers to investigate brain function, and the cells and circuits governing it, in unprecedented detail. My group uses optogenetics and other tools to investigate pain circuits: how they signal and are modulated, what individual cell groups do within the circuit, how complex and dynamic responses to pain are organised, and what alterations in the system result in chronic pain states.

To improve knowledge about a key descending pain modulatory system, we used optogenetics to selectively stimulate one part of this pathway in isolation. We focused on the final synapse made between projection neurons located in the brainstem and neurons in the dorsal horn of the spinal cord, where nociceptive signals first enter the central nervous system. We found that brainstem inputs release the neurotransmitter glycine along with GABA and signal through a multitude of different neuronal types throughout the spinal dorsal horn. Then we showed that activation of kappa-opioid receptors reliably inhibits transmitter release from these descending inputs. This study improves our mechanistic understanding of how descending pain pathways and opioids control pain sensation and enhances our ability to design and develop safe and effective new analgesics. In addition to this example of how optogenetic tools are valuable in neuroscience research, I will also framework some of the ongoing experimental challengers using optogenetic tools to investigate neuronal function.