Bourane S, Grossmann KS, Britz O, Dalet A, Del Barrio MG, Stam FJ, Garcia-Campmany L, Koch S,Goulding M. Identification of a spinal circuit for light touch and fine motor control. Cell. 2015;160:503-15.
Sensory (Sensation feelings) circuits in the dorsal spinal cord (top side of the spinal cord where the sensory nerves send their signals up to the brain) integrate and transmit multiple cutaneous sensory modalities (feelings from the skin) including the sense of light touch (light touch). Here, we identify a population of excitatory interneurons (nerves that transmit between nerve circuits. They can send inhibitory signals to dampen the nerve impulse. But in this case they excite the nerve which they contact.In the media they have dubbed this the mini brain.you could call them balance sensors of feeling in the feet) in the dorsal horn (top left and right of the grey matter in the spinal cord) that are important for transmitting innocuous (non-painful) light touch sensation. These neurons express the ROR alpha (RORα. RAR-related orphan receptor alpha, also known as NR1F1 (nuclear receptor subfamily 1, group F, member 1) nuclear orphan receptor and are selectively innervated by cutaneous low threshold mechanoreceptors (LTMs) (movement sensors in the skin that sense light touch). Targeted removal of RORα interneurons in the dorsal spinal cord (Gene knockout) leads to a marked reduction in behavioral responsiveness to light touch without affecting responses to noxious (painful) and itch stimuli. RORα interneuron-deficient mice also display a selective deficit in corrective foot (movement/balance problems) movements. This phenotype, together with our demonstration that the RORα interneurons are innervated by corticospinal (nerves between the brain cortex and spinal nerves) and vestibulospinal projection neurons (nerves between orientation sensors in the brain and movement nerves), argues that the RORα interneurons direct corrective reflex movements by integrating touch information with descending motor commands from the cortex and cerebellum(There exists group of nerves in the spinal cord that form a relex arc between the positional location of the feet, sensory position of the head, and this then will link back down to the leg muscles for corrective movements to control balance and position. This allows you to keep steady without even thinking about it so it is like a gyroscope).
So if this area gets a lesion during MS this could lead to problems in posture. However it shows that areas of fine movement control are not all in the brain. Could this be used for treatment?....Maybe
Labels: Neural circuitary