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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.


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


  • Judith V. says:

    What is the effect of cervical spine fusion as it relates to the processes described above?

  • Earl D Freeman says:

    Wow what an amazing image.

  • coachl2014 says:

    You have a great talent there, Jamie. Thank you.

  • Zuccheri Gianni says:

    Motor neuron blackout still for how long without therapy?
    While these beautiful images arouse admiration, a thought takes over that turns into sadness. The decline of neurons, in this particular case I am referring to motor neurons.
    I think of the patients with amyotrophic lateral sclerosis, of those I have visited, with their pain frozen in silence.
    I formulate a hypothesis about the cause of this disease: I noticed the same chemical compound in the environment in which some of these patients worked. In different conditions and contexts, both in terms of place and timing.
    A singular coincidence, even if for a very limited number.
    From the gaze of a patient, whose last remaining movement was that of the eyes: his gaze was his voice asking for help.
    ..And the hope emerges that your scientific research will soon heal these sufferings

  • George says:

    Understanding of many things related to the central and peripheral nervous systems are somewhat at their infancy. Cells differentiate into specialized functions based on the milieu . . . a pluripotent cell can differentiate into either neurons or cardiomyocytes based on the growth factors and signals it receives . . . rushing into the clinic can have consequences, and usually the consequences slam the door shut on any further investigation. Ocular indication causing cancer is one aspect, but can you imagine the havoc caused by cells implanted for supplementing L-dopa or insulin turning into cardiomyocytes? For someone peering through a microscope, that will certainly bring butterflies to one’s stomach . . .

    • Zuccheri Gianni says:

      When we drive, the faster we go, the faster we will have to recognize the directions that the cars around us take, on the motorway we have to scan the direction indicators more quickly than when we travel peacefully in the countryside.
      So for the cells that we proliferate to replace the lost ones, starting from totipotent lines:
      to avoid that they take the wrong path of development, or we have early direction indicators or … we reduce the speed of replication with modulatory mechanisms, so that we can stop an unwanted drift in time. If only it were easy …

      • Zuccheri Gianni says:

        To this observation, an intuitive solution would come from reading the article
        ” The Amazing Brain: Tracking Molecular Events with Calling Cards”
        We find an idea of what could be the development direction indicators of cell lines from one
        Undifferentiated cell (called in this contested Calling Cards).
        Could the thermal variation of the environment in which cells grow be a valid means of modulating their growth rate?

  • F.P. says:

    It’s great news. Good job, Jamie.

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