Learning Pyramid and Functional Neurology: The Neuromechanics the Diagram Simplifies

Learning pyramid and functional neurology: same force, different movement

For LabO RNP, functional neurology is the neurology of movement, or neuromechanics. The learning pyramid of Williams and Shellenberger gives a very simplified visual of it. Beneath its boxes, in the model we teach, the brainstem stabilizes the body before the movement (proactive reflex stability) and the cerebellum corrects it during the movement (retroactive reflex stability).

Hello to you, the movement professional,

Two players from the same group step onto the force plate. In the vertical jump, their curves almost overlap: same peak force, same height. Then you ask them for a lateral bound with a single-leg landing, while a partner throws them a ball. The first lands with his eyes still on the ball. The second touches the ground in two stages, the knee looks for its place, and the ball gets away from him one time out of three.

The muscles produce the same force, the plate showed it. So where is the difference decided?

Upstream of the muscle. The learning pyramid of Williams and Shellenberger helps you spot the level that drops out, but it remains a very simplified visual of what is called functional neurology: the neurology of movement, or rather neuromechanics.

Functional neurology and neuromechanics: reading the system that produces the movement

The term circulates with several meanings. At LabO RNP, it designates the first module of the Level 1 training, devoted to the brainstem and the cerebellum. It studies how the nervous system organizes the stability and precision of a movement, upstream of the force that propels it.

Research has a name for this field. For Kiisa Nishikawa and her colleagues (2007), neuromechanics studies how muscles, sense organs, motor pattern generating networks and the brain interact to produce coordinated movement, even in the face of an unexpected perturbation. Information circulates there in a loop, from the brain to the spinal cord, to the muscles, to the body, then back to the brain.

Biomechanics describes angles, levers and forces; neuromechanics goes up one notch, toward the reason why the system chose that movement. The article biomechanics or neuromechanics shows how the two lenses complement each other. Observing how systems produce movement is a reading; looking for a lesion remains the doctor's job.

Seen from this angle, the pyramid drawn in 1991 by Kathleen Taylor and Maryann Trott lists outcomes: body schema, eye-hand coordination, postural adjustment. The loops that produce these outcomes stay outside the drawing, and two structures hold a good part of them.

Brainstem and posture: proactive reflex stability

The brainstem connects the brain, the cerebellum and the spinal cord. Its three segments, the midbrain, the pons and the medulla, house the nuclei of ten of the twelve pairs of cranial nerves. There you also find the reticular formation, a network of neurons that takes part in regulating tone and arousal. Kaoru Takakusaki (2017) describes the role of the reticulospinal pathway in the level of muscle tone, and that of the vestibulospinal pathway in balance.

Raise an arm quickly, standing: the muscles of your legs and trunk changed activity before the shoulder's. Jean Massion (1992) made these anticipatory postural adjustments a centerpiece of his analysis of the coordination between posture and movement. Alexander Aruin and Mark Latash (1995) measured them in people standing on a force plate. The electrical activity of the postural muscles changes before the first burst of the prime mover, with a pattern that depends on the direction of the movement.

Where does this signal start? Takakusaki locates the programming of these adjustments in the motor areas of the cortex, relayed by the corticoreticular and reticulospinal pathways. In the cat, Bénédicte Schepens and Trevor Drew (2004) recorded 142 neurons of the pontomedullary reticular formation during a reaching movement. More than half (58%) increased their activity before the movement started.

This is what LabO RNP calls proactive reflex stability: the cortex decides, and the brainstem lays the base before the movement leaves. The article on the reticulo-pontomedullary formation tells its story, the one on the brainstem, conductor of movement puts the whole region back in place. In the second player, look at what happens just before the take-off: does the trunk lock in, does the support loading happen, or does everything get sorted out in the air?

Cerebellum and movement: retroactive reflex stability

The cerebellum regulates a movement that the cortex has launched. It receives a copy of the command and the feedback from the sensors, compares what was planned with what was done, and corrects. Daniel Wolpert, Chris Miall and Mitsuo Kawato (1998) gathered the arguments in favor of internal models housed in the cerebellum, able to predict the consequences of a command. Reza Shadmehr and his colleagues (2010) describe how these predictions are used to correct error and adapt the movement from one trial to the next.

The most studied example lies in your gaze. When your head turns, the vestibulo-ocular reflex turns your eyes the opposite way to keep the image sharp, and when the image slips repeatedly across the retina, the cerebellum gradually recalibrates its gain. Masao Ito proposed this flocculus hypothesis in the early 1970s and published its synthesis in 1982. Debated since, it remains a classic model of motor learning.

The machine is dense. Frederico Azevedo and his colleagues (2009) counted an average of 86 billion neurons in the brain of adult men, of which only 19% in the cerebral cortex. The cerebellum concentrates about 69 billion, around 80% of the total. In training, its role is summarized by the ABC of movement: precision and fluidity, balance and tone, coordination. The consensus paper published in 2012 by Mario Manto and seventeen colleagues acknowledges that its precise role in movement remains debated. For the learning side, read the cerebellum and learning.

The two stabilities work together. Marcio Santos, Neeta Kanekar and Alexander Aruin (2010) disturbed the balance of eight standing people with a push at shoulder level. When the push was unpredictable, no anticipatory adjustment appeared, only corrections after the fact. When it was predictable, strong anticipatory activity preceded the impact, corrections decreased and the center of pressure moved less. In this experiment, the better the base was laid beforehand, the less was left to catch up afterward.

Table: the five levels of the pyramid and the loops that carry them

This correspondence is our reading, built on published neurophysiology and carrying no value as a validated assessment tool. Level 3 is detailed in the article on sensorimotor development, level 4 in the one on perceptual-motor development.

The neuromechanical reading of a movement: three questions, then tone

In Neuro-Postural Reprogramming, a movement is read from what informs it, with three questions.

How does the head move? The vestibule, housed in the inner ear, measures its rotations, its accelerations and its tilt relative to gravity, and it feeds both gaze and posture. Where are the eyes, and how do they move? They fixate, follow, jump from one target to another, and a gaze that drops out changes what follows in the movement. How does the body move in space and in time? The sensors of the muscles, tendons and skin, which form the sensory foundation of the pyramid, answer that one.

These three channels feed the sensorimotor loop, and the system doesn't trust them equally depending on the situation. Robert Peterka (2002) showed that the more the ground or the visual environment moves, the more posture relies on the vestibule.

Then comes the fourth question: what baseline tone facilitates the movement, that of the flexors or that of the extensors? A single-leg landing requires antigravity extensors ready before contact, and textbooks describe the vestibulospinal pathway as a facilitator of these extensors. The vestibulospinal reflex is its visible version. The episode on flexor and extensor tone develops this question.

Run the second player through the sieve again: his head turns toward the ball, his eyes let go of it at impact, his body lands in two stages. Each of these responses opens a lead to check.

What science establishes, what the training models

Anticipatory and compensatory postural adjustments, the contribution of the reticular formation to posture, error correction by the cerebellum and the calibration of the vestibulo-ocular reflex are established. They are published and replicated, and appear in textbooks such as that of Eric Kandel and his colleagues. Neuromechanics is a recognized field of research.

Other elements belong to the teaching model. Assigning proactive stability to the brainstem and retroactive stability to the cerebellum is a pedagogical simplification. The cerebellum also predicts, through its internal models, and Takakusaki gives it a role in modulating posture; the vestibulospinal reflexes, for their part, also respond after a perturbation. The same goes for the ABC of movement and for the three-question reading grid. These are readings taught in training, useful for observing, without validation as measurement tools. The pyramid itself remains a practitioners' model, without an original study.

A limit also touches the retest. An improvement after a stimulation shows that an output has changed, without saying which structure was affected: the warm-up, familiarity with the test or the person's expectation sometimes suffice to explain the gain.

In the field: observe the landing before testing

The second player already gives you something to observe, without adding anything to the session. The game sends him balls whose trajectory can be read early, and others that surprise him. Santos's experiment is a reminder that the system organizes itself differently depending on whether it can anticipate or has to catch up. What you notice from one situation to another remains an observation, to be cross-checked with the rest of your reading.

Your three questions then direct your gaze toward the head, the eyes or the body. What comes after belongs to the test, stimulation and retest cycle, with the limit seen above: a retest that improves shows that an output has changed, without pointing to the structure at play. The real task, the landing with a ball, will tell whether the change matters in the field.

The boundary with the medical examination stays fixed. Dizziness, double vision, sudden loss of balance, numbness on one side, an unusual sign after a blow to the head: you stop the session and refer to the doctor. In a child where a level seems to give way to the point of weighing on school or daily life, the assessment falls to the doctor, the occupational therapist or the psychomotor therapist. You observe and refer, then you work on the movement.

Back to the two players: where the difference was decided

The plate measured what the muscles could produce. The landing with a ball showed, in the reading we teach, what the brainstem laid down before take-off and what the cerebellum caught during. The pyramid tells you the level; neuromechanics helps you read the loop that carries it. To put each level back in the whole, return to the learning pyramid and its five levels.

When the force is the same, look at what the nervous system laid down before the movement and what it corrects during.

👉 I want to be among the professionals who read the loop upstream.

Frequently asked questions about the learning pyramid and functional neurology

What is functional neurology at LabO RNP?

It is the neurology of movement, which can also be called neuromechanics: the reading of how the nervous system produces a movement, beyond the muscle alone. It is the first module of the LabO RNP Level 1 training, devoted to the brainstem, which stabilizes the body before the movement, and to the cerebellum, which corrects it during.

What is the link between the Williams and Shellenberger pyramid and functional neurology?

The Taylor and Trott pyramid, taken up by Williams and Shellenberger, arranges twenty-two skills across five levels. It is a very simplified visual: beneath its boxes, nerve loops, especially those of the brainstem and the cerebellum, produce the stability and precision of movements. Functional neurology reads these loops.

What is proactive reflex stability?

It is the name LabO RNP gives to the stabilization the nervous system sets up before a voluntary movement. Research describes it under the name of anticipatory postural adjustments: when you raise an arm quickly, the muscles of your trunk and legs change activity before the shoulder's. In the cat, a majority of the neurons recorded in the brainstem reticular formation become active before the movement starts.

What is the role of the cerebellum in movement?

The cerebellum regulates the movements the cortex launches. It compares the planned movement with the performed movement, corrects the error and adapts the movement from one trial to the next, for example by recalibrating the vestibulo-ocular reflex. LabO RNP calls this side retroactive, or compensatory, reflex stability. Its precise role is still debated among researchers.

What is the difference between biomechanics and neuromechanics?

Biomechanics describes visible movement: angles, levers, forces. Neuromechanics studies how the brain, the sense organs and the muscles interact to produce this movement, including in the face of a perturbation. It serves to understand why the system organized the movement in this way.

Where does the movement professional's reading stop?

They observe the movement, form a hypothesis and put it to the test through test, stimulation and retest. Naming a neurological cause is the doctor's job: dizziness, double vision, sudden loss of balance or an unusual sign after a blow to the head require stopping and referring. In children, the assessment falls to the doctor, the occupational therapist or the psychomotor therapist. LabO RNP is neither medical nor paramedical, and is added as a complement to a care pathway, never in its place.

Sources

Taylor K., Trott M. (1991). Pyramid of Learning, in Williams M.S., Shellenberger S. (1996). How Does Your Engine Run? A Leader's Guide to the Alert Program for Self-Regulation. Albuquerque: TherapyWorks.

Kandel E.R., Koester J.D., Mack S.H., Siegelbaum S.A. (2021). Principles of Neural Science, 6th edition. New York: McGraw Hill.

Nishikawa K. et al. (2007). Neuromechanics: an integrative approach for understanding motor control. Integrative and Comparative Biology, 47(1), 16-54.

Takakusaki K. (2017). Functional neuroanatomy for posture and gait control. Journal of Movement Disorders, 10(1), 1-17.

Massion J. (1992). Movement, posture and equilibrium: interaction and coordination. Progress in Neurobiology, 38(1), 35-56.

Aruin A.S., Latash M.L. (1995). Directional specificity of postural muscles in feed-forward postural reactions during fast voluntary arm movements. Experimental Brain Research, 103(2), 323-332.

Schepens B., Drew T. (2004). Independent and convergent signals from the pontomedullary reticular formation contribute to the control of posture and movement during reaching in the cat. Journal of Neurophysiology, 92(4), 2217-2238.

Wolpert D.M., Miall R.C., Kawato M. (1998). Internal models in the cerebellum. Trends in Cognitive Sciences, 2(9), 338-347.

Shadmehr R., Smith M.A., Krakauer J.W. (2010). Error correction, sensory prediction, and adaptation in motor control. Annual Review of Neuroscience, 33, 89-108.

Ito M. (1982). Cerebellar control of the vestibulo-ocular reflex: around the flocculus hypothesis. Annual Review of Neuroscience, 5, 275-296.

Azevedo F.A.C. et al. (2009). Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain. Journal of Comparative Neurology, 513(5), 532-541.

Manto M. et al. (2012). Consensus paper: roles of the cerebellum in motor control. The diversity of ideas on cerebellar involvement in movement. The Cerebellum, 11(2), 457-487.

Santos M.J., Kanekar N., Aruin A.S. (2010). The role of anticipatory postural adjustments in compensatory control of posture: 1. Electromyographic analysis. Journal of Electromyography and Kinesiology, 20(3), 388-397.

Peterka R.J. (2002). Sensorimotor integration in human postural control. Journal of Neurophysiology, 88(3), 1097-1118.

By the LabO RNP team