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The Amazing Brain: Motor Neurons of the Cervical Spine

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Today, you may have opened a jar, done an upper body workout, played a guitar or a piano, texted a friend, or maybe even jotted down a grocery list longhand. All of these “skilled” arm, wrist, and hand movements are made possible by the bundled nerves, or circuits, running through a part of the central nervous system in the neck area called the cervical spine.

This video, which combines sophisticated imaging and computation with animation, shows the density of three types of nerve cells in the mouse cervical spine. There are the V1 interneurons (red), which sit between sensory and motor neurons; motor neurons associated with controlling the movement of the bicep (blue); and motor neurons associated with controlling the tricep (green).

At 4 seconds, the 3D animation morphs to show all the colors and cells intermixed as they are naturally in the cervical spine. At 8 seconds, the animation highlights the density of these three cells types. Notice in the bottom left corner, a light icon appears indicating the different imaging perspectives. What’s unique here is the frontal, or rostral, view of the cervical spine. The cervical spine is typically imaged from a lateral, or side, perspective.

Starting at 16 seconds, the animation highlights the location and density of each of the individual neurons. For the grand finale, viewers zoom off on a brief fly-through of the cervical spine and a flurry of reds, blues, and greens.

The video comes from Jamie Anne Mortel, a research assistant in the lab of Samuel Pfaff, Salk Institute, La Jolla, CA. Mortel is part of a team supported by the NIH-led Brain Research through Advancing Innovative Neurotechnologies® (BRAIN) Initiative that’s developing a comprehensive atlas of the circuitry within the cervical spine that controls how mice control their forelimb movements, such as reaching and grasping.

This basic research will provide a better understanding of how the mammalian brain and spinal cord work together to produce movement. More than that, this research may provide valuable clues into better treating paralysis to arms, wrists, and/or hands caused by neurological diseases and spinal cord injuries.

As a part of this project, the Pfaff lab has been busy developing a software tool to take their imaging data from different parts of the cervical spine and present it in 3D. Mortel, who likes to make cute cartoon animations in her spare time, noticed that the software lacked animation capability. So she took the initiative and spent the next three weeks working after hours to produce this video—her first attempt at scientific animation. No doubt she must have been using a lot of wrist and hand movements!

With a positive response from her Salk labmates, Mortel decided to enter her scientific animation debut in the 2021 Show Us BRAINs! Photo and Video Contest. To her great surprise and delight, Mortel won third place in the video competition. Congratulations, and continued success for you and the team in producing this much-needed atlas to define the circuitry underlying skilled arm, wrist, and hand movements.

Links:

Brain Research through Advancing Innovative Neurotechnologies® (BRAIN) Initiative (NIH)

Spinal Cord Injury Information Page (National Institute of Neurological Disorders and Stroke/NIH)

Samuel Pfaff (Salk Institute, La Jolla, CA)

Show Us Your BRAINs! Photo and Video Contest (Brain Initiative/NIH)

NIH Support: National Institute of Neurological Disorders and Stroke