To ensure the speed of our reflexes, the connections are managed by interneurons located in the spinal cord. A “short circuit” which ensures the immediacy of the reaction.
- Our reflexes are managed at the level of the spinal cord, to avoid wasting time going through the brain
- Each reflex is defined by neurons in the same physical space
When you touch a hot pan, your hand moves away by reflex; if you miss a rung while climbing a ladder, you instinctively catch up at the rung. These two movements take a fraction of a second and do not require any prior thought. Researchers from the Salk Institute succeeded in explaining them by mapping the physical organization of cells in the spinal cord.
Understanding the architecture of our sensory-motor system
The discovery of this new pattern of our sensory-motor system, first described in the journal Neuroncould help relieve chronic pain or itching.
“A lot of research has been done on the periphery of this system, looking at how skin and muscle cells generate signals, but we didn’t know how that sensory information is processed and interpreted once it reaches the medulla. spinal”, explains Martyn Goulding, professor of molecular neurobiology. “This new essay provides a fundamental understanding of the architecture of our sensory-motor system,” continues the scientist.
The function of interneurons
To ensure our reflexes and our survival, the connections are ensured by interneurons located in the spinal cord, which act as a kind of intermediaries and save time by bypassing the brain. How these intermediaries are organized to encode reflexes has until now been poorly understood.
“What we discovered was that each reflex was defined by neurons in the same physical space,” says Graziana Gatto, director of research. “Different neurons in the same location, even though they had very different molecular signatures, performed the same function, while more similar neurons in different areas of the spinal cord were responsible for different reflexes.” Specifically, interneurons in the outermost layer of the spinal cord are responsible for itch-related reflexes. Deeper interneurons relay pain messages.
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