Grey matter of the spinal cord

What the sources say

“Gray Horns In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.”” Betts et al. 2022, §13.2

“The posterior horn is responsible for sensory processing.” Betts et al. 2022, §13.2

“The anterior horn sends out motor signals to the skeletal muscles.” Betts et al. 2022, §13.2

“The lateral horn , which is only found in the thoracic, upper lumbar, and sacral regions, contains cell bodies of motor neurons of the autonomic nervous system.” Betts et al. 2022, §13.2

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• Autonomic outflow and the bladder

  Where the cord sends its automatic, involuntary commands. Sympathetic outflow leaves from the thoracic and upper lumbar cord, parasympathetic from the brainstem and sacral cord, and the bladder shows how both work with voluntary control.

• Central pattern generators

  The spinal circuits that can produce the rhythm of stepping on their own. Graham Brown's half-centre idea, where the circuits sit, and why they matter for walking again after spinal cord injury.

• Gate control of pain

  Melzack and Wall's 1965 idea that the dorsal horn of the cord works like a gate on pain signals, opened or closed by other inputs and by the brain. What it proposed, what it changed, and how it is described now.

• Grey matter and Rexed laminae

  The H-shaped core of the cord. Its horns sort sensory input, drive muscles and run autonomic outflow, and the dorsal horn is layered into laminae that receive different kinds of sensation.

• The spinal cord

  The part of the central nervous system inside the vertebral column. How it is built from grey horns and white columns, why it is shorter than the column, and how its regions are named.

• The stretch reflex

  The knee jerk explained. A stretched muscle's spindle makes the same muscle contract directly through the cord and relaxes its antagonist, keeping the muscle at a constant length.

• The withdrawal reflex

  Pulling away from a hot stove or a tack. Pain excites the motor neurons of the withdrawing muscle and, through an inhibitory interneuron, quiets the opposing muscle so the movement is faster.