Venue : Centre Broca
Louison Brochoire
Team : Monoamines, Parkinson and Pain
IMN
Title
Development and implementation of innovative techniques for the functional study of dorsal horn neurones in the mouse spinal cord
Abstract
My thesis focused on the study of somatosensation and pain. Despite the critical role of the dorsal horn of the spinal cord as the primary site for processing and relaying somatosensory information, the underlying neuronal circuits and mechanisms remain poorly understood. Recent studies have identified a population of neurons expressing the Tachykinin 1 (Tac1) gene, which are essential for coping behaviors induced by intense noxious stimuli. However, the nature and functional properties of these neurons are still not fully described. In the first part of my PhD, I performed a thorough characterization of Tac1 neurons using slice electrophysiology and in vivo imaging techniques in both naïve and neuropathic conditions following sciatic nerve injury. These results revealed a neuronal population predominantly composed of polymodal nociceptors under physiological conditions, whose properties are altered following sciatic nerve injury. On the other hand, most studies investigating spinal cord electrophysiological properties have relied on in vitro preparations or anesthetized animals. However, neuronal activity and properties can differ substantially under these conditions compared to the awake state. Studying neuronal activity in awake, freely moving animals has been limited by the technical challenges related to spinal cord inaccessibility. In the second part of my project, we developed and introduced a novel electrode system to record from the dorsal horn of the spinal cord in freely moving mice. Using this approach, we demonstrated that spontaneous spinal activity varies according to the animal’s state of arousal and that the encoding of sensory information depends on the integrated modalities. Taken together, our results provide new insights into the role of the dorsal horn in processing somatosensory information in both naïve and neuropathic conditions.
Key words
Spinal cord, Tachykinin 1, Somatosensation, Pain, Freely moving