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BE 421/521 Final Paper / Presentation
Final Paper
Rough draft: Due Thursday, November 29th, 2018 in class so that you can exchange the rough
draft with a classmate and give each other constructive feedback.
Final draft: Due Thursday, Dec 13th, 2018 during exam session
The final paper is a written report of a particular control system involved in human movement.
The paper should introduce your system of choice, describe the impact of this system on human
movement, and explore in detail the features of the system (inputs, outputs, modulating
components, feedback, etc.). You may wish to consider what occurs when this system is
broken/diseased, and new avenues of research involving this system. Use structured subheadings
to improve the clarity and organization of your paper. Be sure to include your annotated diagram
and refer to it in the text!
Your paper should:
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Be 9 pages (undergraduate) or 12 pages (graduate) excluding references
Use 12-point font
Be double-spaced
Have 1” margins
Include your annotated diagram (and other diagrams as necessary)
Have clear writing without typos … please enlist a friend or family member to proofread
your work!
Include at least 10 primary source articles. The references should be cited in the text like
this (Johnson et al., 2014) with the full references in a section after your text like this:
References (the first ref below is for journal articles, the second is for a book)
Johnson UA, Movement NC, Control F (2014) How to include references in your paper topic.
Journal of our class 1(2): 203-204.
Zancolli E (1979) Structural and dynamic bases of hand surgery. Philadelphia: Lippincott.
Final Presentations
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This is an oral presentation of your final paper.
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Presentations will be on December 6th and 13th. We will decide on the order of presenters
after the Thanksgiving break.
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Presentations will be 10 – 12 minutes in length, followed by a few minutes for questions
from me and the rest of the class. You are expected to ask questions to other presenters at
some point and will be given participation points based on this.
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Plan on preparing 8 – 12 slides for your presentation. 1 – 2 minutes per slide is a good
rule of thumb for presentations.
Babinski Reflex
1.0 Introduction
The Babinski reflex is a common assessment tool used by neurologists for determining
the integrity of spinal reflexes and the corticospinal tract. It is stimulated by stroking the sole of
the foot with a blunt instrument (Mortimer, Maricle, Neuhaus, & Konstam, 2011) (Fig. 1).
Specifically, the reflex is elicited by running the object along the lateral plantar border of the foot
near the heel, crossing the metatarsal pads (i.e. ball of the foot) and ending near the hallux (i.e.
big toe) (Khwaja; Van Gijn, 1995) (Fig. 1). If this stroking motion causes hallux dorsiflexion,
also known as hallux extension, the response is considered normal in infants. Paradoxically, the
hallux extensors (in anatomical terms) are considered flexor muscles in a physiological sense.
Thus, hallux dorsiflexion and extension describe the same movement, the movement of the
hallux closer to the shin, while hallux plantar flexion and flexion describe the opposite
movement (Van Gijn, 1995). Hallux dorsiflexion during the Babinski reflex test is considered
abnormal if it persists after the age of two (Kumar, 2003; Pauc; Walker, Hall, & Hurst, 1990).
Figure 1. A typical commercially available Babinski hammer (left) (http://mdpocket.com/telescopicbabinski-reflex-hammer.html). The metal side of the object should be pressed against the skin. The blunt
ends of reflex hammers and thumbnails are also commonly used. Path that the object should follow
(right).
The naming convention for resulting hallux dorsiflexion or plantar flexion is called a
positive and negative Babinski sign, respectively. This terminology is named after the French
neurologist, Joseph Babinski, who first discovered this phenomenon at the end of the 19th
century (Bruno, Horacio, Yolanda, & Guillermo). The purpose of this paper is to provide an indepth review of the control mechanisms involved in the Babinski reflex and how the maturing
brain can modulate reflexes. It will also describe how a positive Babinski sign in non-infants can
be used to help diagnose a lesion in the central nervous system. The Babinski reflex in infants is
first described in detail, followed by the reflex in adults.
2.0 Infants
2.1 Phalangeal Dorsiflexion
Foot stimulation from the blunt object is detected by cutaneous receptors in the S1
dermatome, an area of skin that is mainly supplied by a single spinal nerve. The afferent signal
then travels up the tibial and sciatic nerves to the L5/S1 nerve root to the dorsal horn of the
spinal cord (Fig. 2). It then travels via interneurons, neurons that serve as the connection point
between sensory and motor pathways, in the spinal cord to the anterior horn to elicit a motor
response (Futagi & Suzuki, 2010). Given that this reflex does not involve higher level control
above the spinal cord in infants, it is a spinal reflex (Futagi, Suzuki, Toribe, & Kato). A motor
response in this spinal reflex occurs via an efferent command from the L5/S1 nerve roots to first
the sciatic nerve and then the tibial and deep peroneal nerves. The deep peroneal nerve then
innervates the extensor hallucis longus muscle (Fig. 3). This muscle arises from the middle
portion of the fibula on the anterior surface of the interosseous membrane and inserts on the
dorsal side of the base of the distal phalanx of the hallux. Since the muscle runs along the top of
the foot and inserts on the top of the hallux, when activated it causes dorsiflexion of the hallux
(Fig. 4). The extensor digitorum longus is also commonly activated during the Babinski reflex.
Since this muscle originates on the anterior lateral condyle of the tibia and inserts on the dorsal
surface of the middle and distal phalanges of the lateral four digits, it dorsiflexes and abducts or
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fans outs the other phalanges of the foot (Deng, Jia, Zhang, Guo, & Yang). Since the hallux has
the largest degree of movement of all the phalanges due to the anatomical structure of the
metatarso-phalangeal joints, movement of the hallux is usually the greatest and therefore the
easiest to monitor during the reflex (Dafkin et al.).
Figure 2. Neural control behavior during a positive Babinski sign.
Figure 3. The positive Babinski reflex involves the activation of the extensor hallucis longus which
dorsiflexes the hallux and frequently also activates the extensor digitorum longus which dorsiflexes the
other phalanges.
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Figure 4. A 5-month old involuntary eliciting a positive Babinski sign (red circle) by accidently applying
pressure along the sole of his left foot with the hallux of his right foot. Figure annotated from (Neelon,
1999).
2.2 Involvement of Leg Flexors as Part of Flexion Withdrawal Reflex
The muscles involved in a positive Babinski sign are responsible for shortening the leg,
consistent with a more general flexion withdrawal reflex that protects the body from painful
stimuli by shortening the limb and removing the limb from the stimuli (Dafkin et al.; Deng et al.;
Sandrini, Serrao, Rossi, & Romaniello). For example, during a positive Babinski sign, the
contraction of the extensors of the phalanges occurs in combination with activation of the tibialis
anterior, the hamstrings (i.e. semitendinosus, semimembranosus and biceps femoris) and the
tensor fasciae latae muscle (Van Gijn, 1995) (Fig. 5). The tibialis anterior originates on the
lateral (outside) surface of the tibia and inserts into the medial cuneiform and first metatarsal of
the foot and acts to dorsiflex and invert the foot (turn the bottom of the foot inward). The
hamstrings originate on the tuberosity of the ischium and linea aspera (ridge of roughened
surface on the posterior surface of the femur), and insert on the tibia and fibula. They act to flex
the knee and extend the hip. The tensor fasciae latae originates on the iliac crest and inserts on
the iliotibial tract and acts to flex the thigh, along with also medially rotating and abducting the
thigh. In summary, these muscles primarily act to flex and thus shorten the leg (Hultborn).
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However, since the big toe is lighter than the foot, shank, and thigh, the activation of these
muscles during the Babinski reflex rarely causes noticeable movement of these body segments.
As will be explained in detail below, as the central nervous system matures, the dorsiflexion of
the phalanges are no longer part of the flexion withdrawal reflex, while the foot, thigh and leg
flexors all remain part of the flexion withdrawal reflex.
Figure 5. The tibialis anterior, hamstring and tensor fasciae latae are also activated during a
positive Babinski sign as part of the flexion withdrawal reflex, although usually not at a sufficient
magnitude to cause visible movement of the foot, shank or thigh.
3.0 Adults
3.1 Negative Babinski Sign
3.1.1 Phalangeal Decoupling from Flexion Withdrawal Reflex
The corticospinal tract is a group of about 1 million nerves that originate in layer V of the
cerebral cortex, primarily from the primary motor cortex (30%) (M1), supplementary motor area
(SMA) and the premotor cortex (30%), and the somatosensory cortex (S1), parietal lobe and
cingulate gyrus (40%) (Walker et al., 1990). The nerves travel from the cortex down to the
spinal cord and cross over at the ventral surface of the medulla in the brainstem (Fig. 6).
Individual nerves terminate at the vertebral level of the muscle that they innervate. However,
most of the nerves do not directly synapse with nerves of the peripheral nervous system such as
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the sciatic nerve, but instead synapse with interneurons. At birth, the corticospinal tract is
unmyelinated, but progressively myelinates during the first two years of life (Deng et al.).
Figure 6. Neural control during a negative Babinski sign. The corticospinal tract is fully myelinated by
around age two, enabling them to inhibit hallux dorsiflexion via the interneurons.
After age two, the Babinski reflex normally results in a negative sign, suggesting the
myelination of the corticospinal tract is the driving factor in the change in the direction of hallux
movement occurring around that age (Deng et al.). Myelination of the corticospinal tract enables
the tract to inhibit the interneurons that cause the hallux to dorsiflex. Thus, corticospinal
involvement in the control of movement represents a higher level of involvement in the central
nervous system (CNS), meaning above the spine or supraspinal. This supraspinal involvement
decouples the phalanges from the more general flexion withdrawal reflex, causing the Babinski
reflex to become a cutaneous reflex (Nakajima, Sakamoto, Tazoe, Endoh, & Komiyama).
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3.1.2 Cutaneous Reflex
Cutaneous reflexes are activated by skin receptors and play a valuable role in locomotion.
They are important in responses to obstacles or stumbling and for making adjustments to
unexpected stimuli (Nakajima et al.). A common result of a cutaneous reflex is the activation of
extension muscles that act to propel the limb and body away from the stimuli (Van Gijn, 1995).
A negative Babinski sign is caused by activation of the flexor hallucis longus muscle. This
muscle originates on the fibula and inserts on the plantar surface of the foot at the base of the
distal phalanx of the hallux (Fig. 7). Since it runs along the bottom of the foot, its activation
causes the hallux to plantar flex. This motion is similar to toe-off during walking or running and
acts to propel the body forward.
Commonly, the flexor digitorum longus muscle is also
activated. This muscle originates on the posterior surface of the tibia and inserts on the plantar
surface of the foot, on the base of the distal region of the 2nd through 5th phalanges and therefore
acts to plantar flex those phalanges (Fig. 7). Again, the activation of these phalangeal flexor
muscles during the Babinski reflex requires a healthy and mature central nervous system that
enables the corticospinal tract to inhibit the flexion withdrawal of the hallux (Chew, Oon, Lee,
Lim, & Tan; Khwaja). Interestingly, for a sleeping healthy adult, the reflex will revert back to
being positive, providing proof that inhibition of the response involves brain activation in an
awake state, even if it is subconscious (Singerman & Lee).
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Figure 7. A negative Babinski reflex involves the activation of the flexor hallucis longus (left) which
plantar flexes the hallux and frequently also activates the flexor digitorum longus (right) which plantar
flexes the other phalanges.
3.2 Positive Babinski Sign in Adults
3.2.1 Testing of Phalangeal and Leg Flexors
A positive Babinski sign in non-infants is a sign of damage to the corticospinal tract such
that it can no longer inhibit interneurons at the sacral level of the spine and the central nervous
system reverts to its neonatal, or primitive, setting (Neelon, 1999). The control mechanisms that
result in hallux dorsiflexion in adults are the same that cause hallux dorsiflexion to occur in
infants (Fig. 2). However, many factors need to be considered prior to concluding that the reflex
results in a positive sign in adults. For example, the change in hallux angle is not objectively
quantified and is only observed by the clinician.
Moreover, the threshold that should be
considered abnormal is not well defined (Mortimer et al.). For example, some clinicians might
consider hallux dorsiflexion of less than 15° worrisome, while others might consider it to be
inconclusive or inconsequential. Therefore, movement of the hallux should not be the only
variable considered during the test (Van Gijn, 1995). As stated above, during a positive Babinski
sign, other limb flexors, such as the tibialis anterior, the hamstrings and the tensor fasciae latae
muscle are activated during a positive Babinski sign since it is part of a more general flexion
withdrawal reflex. The examiner can either palpate over these muscles during the test to feel if
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they tighten or try to observe the thigh, shank and foot for movement to confirm a positive
Babinski sign (Van Gijn, 1995). The examiner should also palpate the extensor hallucis longus
muscle during the test to confirm that it tightens. This can help rule out hallux dorsiflexion
occurring from passive movement. Additionally, the reflex should be conducted on both feet,
and the tests should not be considered abnormal unless the change in hallux angle in dorsiflexion is
clearly asymmetrical, compared to the ipsilateral side (Mortimer et al.).
3.2.2 Other Stimulation Tests and Reliability of Babinski Reflex
Other stimulation tests that produce Babinski-like responses are usually also conducted to
confirm a positive Babinski sign. These include stroking the lateral malleolus (Chaddock sign),
applying pressure down the medial side of the tibia (Oppenheim sign), squeezing the calf
(Gordon sign) or Achilles tendon (Schaeffer sign), or flexing and then quickly releasing the
fourth phalanx (Gonda sign) (Mortimer et al.).
However, the Babinski sign is considered the
most reliable of these tests since it has the highest reported inter-rater consistency, with a kappa
value (i.e. the degree of agreement actually achieved above chance divided by the degree of
agreement that is attainable above chance) of 0.5491 (Singerman & Lee). By comparison, the
Chaddock, Oppenheim, and Gordon reflexes have kappa values of 0.4065, 0.3739, and 0.3515,
respectively (Singerman & Lee).
Besides the previously described qualitative instead of
quantitative assessment of the change in hallux angle, one the other biggest factors of inter-rater
and intra-rater inconsistencies in these tests is that they are conducted manually by the examiner,
introducing a high degree of variability in the duration of stroke and maximum and average force
applied during the tests (Dafkin et al.; Ross, Velez-Borras, & Rosman). This likely influences
the interpretation of these tests since the Spearman’s rank correlation between duration of stroke,
maximum and average force and change in hallux angle all have significance values (p) of equal
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to or less than 0.01 (Dafkin et al.). Moreover, there is a wide range of sensitivity (i.e. actual
positives which are correctly identified, also known as the true positive rate) and specificity (i.e.
the proportion of negatives which are correctly identified, also known as the true negative rate)
values reported for the Babinski reflex. The published sensitivity and specificity values range
from 20 – 80% and 80 – 96%, respectively (Cook, Hegedus, Pietrobon, & Goode; Miller &
Johnston). As a whole, the lower sensitivity values and higher specificity values appear to make
it more likely that someone with a corticospinal tract lesion will have a negative Babinski sign,
compared to a healthy individual having a positive Babinski sign. Given the above uncertainties
with the Babinski reflex, it should not be the only test conducted during a neurological exam and
other tests should be conducted to validate its findings (Cook et al.).
3.2.3 Cortical vs. Sub-cortical Lesions
While a positive Babinski sign cannot be used to determine the exact location of the
lesion to the corticospinal tract, there has been research on whether isolated hallux dorsiflexion
compared to hallux dorsiflexion in combination with dorsiflexion and fanning out of the 2nd
through 5th phalanges can be used to determine whether the lesion is cortical or subcortical
(Deng et al.).
Specifically, 107 subjects with lesions of the corticospinal tract confirmed with
medical imaging were put into two groups: 1) Sub-cortical lesions, with lesion in the corona
radiata to spinal cord (n = 93); and 2) Cortical lesions (n = 14) (Fig. 8). Of the 93 patients in the
sub-cortical group, 4% had isolated hallux dorsiflexion and 96% had recruitment of the other
phalanges. By contrast, in the cortical group, 71% had isolated hallux dorsiflexion and 29% had
dorsiflexion and/or fanning out of other phalanges.
The authors concluded that since the
corticospinal fibers are more centralized within the brainstem and vertebral canal, a small lesion
in the spinal cord can bring about more generalized symptoms due to a greater number of
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neurons affected, whereas a lesion in the cortex likely affects less pathway fibers because the
fibers are more diffuse in the cortex (Deng et al.). In essence, the fibers are bundled together in
the smaller volume of the spinal cord and thus a lesion at that location causes more generalized
symptoms since it affects more fibers at that bottle-neck location.
Figure 8. Example of lesions, identified by arrows, from cortical (left) and sub-cortical groups (right).
The cortical lesion group mostly had isolated hallux dorsiflexion, while the sub-cortical group had
combined hallux and 2nd through 5th phalangeal dorsiflexion and fanning out.
3.2.4 Follow-up Clinical Testing and Imaging
Although the degree of phalangeal involvement may help determine if the lesion is
cortical or sub-cortical, a positive Babinski sign cannot be used to make a differential diagnosis
since a positive sign can be caused by a wide range of diseases related to compromised spinal
cord and brain function. These include a lesion impinging the spinal cord, a brain tumor along
the corticospinal tract, meningitis, multiple sclerosis, stroke, rabies, amyotrophic lateral sclerosis
(ALS), hepatic encephalopathy, and cerebral palsy (Mortimer et al.). A combination of followup brain and spine MRIs, cerebral angiography, lumbar puncture, cerebrospinal fluid (CSF)
analysis, and somatosensory evoked potentials (SEP) are usually needed to make a differential
diagnosis about the classification and exact location of the lesion to the corticospinal tract
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(Mortimer et al.). Individuals who have a positive Babinski sign usually have concomitant
weakness, incoordination and general difficulty with muscle control, alerting the physician to a
potential problem prior to testing the Babinski reflex. However, the testing of the Babinski
reflex is a quick, easy and cheap clinical test for neurologist to use to determine if the pathology
involves the corticospinal tract prior to ordering expensive and time consuming clinical testing
and imaging.
4.0 Conclusion
The purpose of this paper was to provide an in-depth review of the control mechanisms
involved in the Babinski reflex and how the maturing brain can modulate reflexes. In infants, the
Babinski reflex results in hallux dorsiflexion since it is part of the more general flexion
withdrawal reflex. This is a spinal reflex with no higher input above the spinal cord. During the
first two years of life, the corticospinal tract myelinates and inhibits hallux dorsiflexion during
the Babinski reflex and from being part of the flexion withdrawal reflex. The decoupling of
hallux dorsiflexion from the flexion withdrawal reflex causes the Babinski reflex to become a
cutaneous reflex, which involves higher input from the brain. Thus, in healthy adults, the
Babinski reflex results in hallux plantar flexion. A reversal of hallux movement from plantar
flexion to dorsiflexion (positive Babinski sign) in adults is a sign of damage to the corticospinal
tract. A positive Babinski finding in adults can be caused by a myriad of diseases and conditions
that affect the corticospinal tract. Although movement of the 2nd and 5th phalanges during the
Babinski reflex can help determine whether damage to the tract is cortical or sub-cortical, further
testing is required to determine the exact location and cause of the damage to the tract.
Nonetheless, the Babinski reflex remains a valuable and inexpensive test for determining the
integrity of spinal reflexes and the corticospinal tract.
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References
Bruno, E., Horacio, S.-M., Yolanda, E., & Guillermo, G. R. (2007). The articles of Babinski on
his sign and the paper of 1898. Neurology India, 55(4), 328.
Chew, K., Oon, L., Lee, R., Lim, K., & Tan, C. (2010). Withdrawal response in healthy adults.
Neurology Asia, 15(2), 159-165.
Cook, C. E., Hegedus, E., Pietrobon, R., & Goode, A. (2007). A pragmatic neurological screen
for patients with suspected cord compressive myelopathy. Physical therapy, 87(9), 12331242.
Dafkin, C., Green, A., Kerr, S., Raymond, A., Veliotes, D., Elvin, A., . . . McKinon, W. (2014).
Kinematic and kinetic analysis of the inter-and intra-applicator assessment of the
Babinski reflex. Neurophysiologie Clinique/Clinical Neurophysiology, 44(5), 471-477.
Deng, T., Jia, J.-p., Zhang, T., Guo, D., & Yang, L. (2013). Cortical versus non-cortical lesions
affect expression of Babinski sign. Neurological Sciences, 34(6), 855-859.
Futagi, Y., & Suzuki, Y. (2010). Neural Mechanism and Clinical Significance of the Plantar
Grasp Reflex in Infants. Pediatric neurology, 43(2), 81-86.
Futagi, Y., Suzuki, Y., Toribe, Y., & Kato, T. (1999). Neurologic outcomes of infants with
tremor within the first year of life. Pediatric neurology, 21(2), 557-561.
Hultborn, H. (2006). Spinal reflexes, mechanisms and concepts: from Eccles to Lundberg and
beyond. Progress in neurobiology, 78(3), 215-232.
Khwaja, G. A. (2005). Plantar reflex. Journal Indian Academy of Clinical Medicine, 6(3), 193197.
Kumar, S. P. (2003). The Babinski sign--a critical review. Journal of the Association of
Physicians of India, 51, 53-57.
Miller, T. M., & Johnston, S. C. (2005). Should the Babinski sign be part of the routine
neurologic examination? Neurology, 65(8), 1165-1168.
Mortimer, J. E., Maricle, D. E., Neuhaus, D., & Konstam, E. (2011). Babinski Reflex
Encyclopedia of Child Behavior and Development (pp. 197-199): Springer.
Nakajima, T., Sakamoto, M., Tazoe, T., Endoh, T., & Komiyama, T. (2006). Location specificity
of plantar cutaneous reflexes involving lower limb muscles in humans. Exp Brain Res,
175(3), 514-525.
Neelon, F. A. (1999). Babinski Sign. Corsini Encyclopedia of Psychology.
Pauc, R. (2011). The Babinski sign in sickness and in health. Clinical Chiropractic, 14(3), 122126.
Ross, E. D., Velez-Borras, J., & Rosman, N. P. (1976). The Significance of the Babinski Sign in
the Newborn—A Reappraisal. Pediatrics, 57(1), 13-15.
Sandrini, G., Serrao, M., Rossi, P., & Romaniello, A. (2005). The lower limb flexion reflex in
humans. Progress in neurobiology, 77(6), 353-395.
Singerman, J., & Lee, L. (2008). Consistency of the Babinski reflex and its variants. European
Journal of Neurology, 15(9), 960-964.
Van Gijn, J. (1995). The Babinski reflex. Postgraduate medical journal, 71(841), 645-648.
Walker, H. K., Hall, W. D., & Hurst, J. W. (1990). Clinical methods.
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Neural Control of Walking and
Running
Is Walking Easy?
How movement preformed?
• A complex neural control system
• Central nervous system
➢It is able of handling various activities at same time
➢Integrate control command in cortical and spinal
➢makes adjustments to these motor commands based
on sensory feedback from a variety of source
➢controls multi joint limbs using a variety of muscles
➢it has control over all voluntary movement such as
running, walking
Spinal cord system
Mutual Crossed Inhibition
Walking to Running
➢ the midbrain sends signals to the spinal cord to communicate when your legs
should start moving, and how fast
➢ the brain first sends a signal to the spinal cord, then nerve cells in the spinal cord
control the precise coordination of the muscles
➢ the difference between walking and running is only the speed and the signals are
sent from the brain
➢ Before the spinal cord can run , it needs signals from the brain and we have now
identified two areas in the midbrain that initiate locomotion and set the speed of
locomotion
➢ the generation of locomotion is in the spinal cord itself, where the process is
automated to a degree
Researching the Spinal Interneurons
Circuit
➢ Great strides have been made in understanding the
organization and function of spinal cord
➢ Researchers still have more to learn, including how
to replace or heal damaged or diseased nerve cells
➢ They show that exercising damaged spinal circuits
improves function
➢ Robotics researchers are borrowing what scientific
have found in the spinal interneuron circuits to
design robots that crawl, walk, or swim like animal
Any questions
NEURON CONTROL OF MOVEMENTS
1
Neural Control of Running and Movement
Name
Institution
NEURON CONTROL OF MOVEMENTS
2
Neural Control of Running and Movement
The research essay explores how the central nervous system in a human being control
movement and running. The brain resembles a central computer system that controls every one
of the elements of a human’s body. At this point, the Nervous System resembles a system that
sends messages back and forth from the brain to various components of the body. It does this
through the spinal cord, which runs starting from the brain through the back and contains
threadlike nerves that stretch out to each organ and body part for effective communication
(Enoka, 2015). The spinal cord roles include controlling motor or movement coordination, but it
has many other functions in the body. Motor control alludes to the way in which nervous systems
create certain kinds of muscle movement. In people, the coordinated relaxation and contraction
of muscle clusters are intervened both by reflex mechanisms and higher-order executive systems
that include broadly appropriated parts of the brain. Controlled movements venture into
subjective areas, and in this way issues of motor control cannot be completely isolated from
other mental processes (Crary, Carnaby, Haak & Madhavan, 2015). The investigation of motor
coordination gives another dissection apparatus to clarify both common and uncharacteristic
examples of movement.
The Central Nervous System
Most systems and organs in our body are capable of regulating one function of the body
at a time, but the case is different when it comes to the central nervous system. It is capable of
handling various activities simultaneously. For example, it has control over all voluntary
movement such as running, walking. On the other hand, it regulates involuntary activities such as
breathing and blinking and is the center of our perceptions, thoughts, and emotions. The nervous
system is comprised of all the nerve cells in the human body. It is through the Nervous System
NEURON CONTROL OF MOVEMENTS
3
that we speak with the outside world, and various instruments inside our body are controlled
(Grassi, Mark & Esler, 2015).
The Nervous system learns through our senses, digest the information and triggers a
series of reactions when needed (Hughes, Sangle & Bowman, 2014). For example, making your
muscles move when burned by a hot object or pierced by a sharp object, signals that originate
from the cerebrum. The sensory system in our body additionally controls metabolic procedures.
There are a vast number of nerve cells referred to as neurons, in the nervous system. The Brain
alone has around 100 billion neurons in it which coordinates hundreds of activities. Every neuron
is made of a cell body and different extensions. The shorter extensions are known as dendrites,
and they carry a similar role to that of the antennae (Nave & Werner, 2014). For instance, they
acquire signals from different neurons and transmit them to the cell body. The signs are then
passed on utilizing a long Extension or what is known as the axon which measures to about one
meter long.
The nervous system has two sections—one called the Peripheral Nervous System and the
central nervous system. Their name is determined by the area of the body they are located. The
(CNS) incorporates the nerves in the spinal cord and the brain. The brain is securely contained
inside the skull while the vertebral canal protects the spine from injuries. The majority of other
nerves in the body are a piece of the peripheral sensory system (PNS) (Hughes, Sangle &
Bowman, 2014). Notwithstanding where they are in the body, the difference can be made among
both involuntary voluntary nervous system. The voluntary nervous system controls every one of
the things that we know about and can consciously impact, for example, moving from one place
to another using our legs, arms, and the rest of body parts of the body such as the head (Wurth,
Courtine & Micera, 2018).
NEURON CONTROL OF MOVEMENTS
4
The involuntary or vegetative Nervous System role is to manage the processes in the
body that human beings cannot consciously impact. It is always active, directing things, for
example, heartbeat, breathing, and metabolic procedures. It does this by acquiring a message
from the brain and transmitting them to the other part of the body. Rather than receiving only it
also send signals the other components such as from the body to the brain. For example, it
furnishes the brain with data about how full your bladder is or how rapidly your heart is beating
(Wurth, Courtine & Micera, 2018).
On the other hand, the involuntary nervous system can respond rapidly to specific
changes such as modifying some functions of the body to adapt to the changing environment. For
example, if your body gets excessively hot, your sensory system builds the blood flow to your
skin and produce sweat more to cool the body. Both the Central and Peripheral Nervous Systems
have Involuntary and Voluntary systems that control the movement. However, they are firmly
connected though they are kept in isolated regions of the body (Wurth, Courtine & Micera,
2018).
As human think, walk, see, breath, laugh, cry and do everything for the day, you are
utilizing your central nervous system to actualize these activities. It is the system that gets and
forms all data from all parts of the body and acts accordingly. It comprises of the vital parts of
the body such as the brain, neurons, and the spinal cord and it is seemingly the most critical
system of the Body. It is alluded to as "Focal" because it joins data from the entire body and
coordinates action based on demand. For example, when one needs to walk slowly or run fast, it
is the system that responds to this kind of requests.
NEURON CONTROL OF MOVEMENTS
5
Parts and Functions of the Central Nervous System
Neurons are the fundamental units that make up the nervous system. All cells of the
system are made of neurons whose role is to communicate to various parts of the body to and
from the brain (Woolsey, Hanaway & Gado, 2017). Neurons can transmit electrical impulses all
through the body as signs that warrant a response. There are three kinds of neurons known as
sensory, motor, and interneurons. Motor neurons transmit data between the muscles, organs, and
the glands in various parts of the body. When the systems of interneurons in the spinal cord
assess and ascertain sensory data it then settles on an activity, they arouse efferent neurons. This
kind of neurons also known as motor neurons role is to convey signals from the gray matter of
the CNS are delivered through the nerves found in the peripheral nervous system to effector
cells. The effector might be smooth, cardiac which discharges a particular hormone or moves a
piece of the body to react to the stimulus (Nave & Werner, 2014).
How the spinal cord works and its various parts.
Sensory neurons transmit data to both the spinal cord and the brain inside and external
organs and stimuli encountered by the parts of the body. The sensory capacity of the nervous
NEURON CONTROL OF MOVEMENTS
6
system includes gathering data from sensory receptors that screen the body's interior and outside
conditions. These signals are then conveyed to the CNS for further preparing by afferent neurons
and nerves. The brain is the control of the body. The mind is commonly considered to have three
principal parts: The brain stem, the forebrain, and the hindbrain. The role of the forebrain is to
get and form sensory data. Example of these includes thinking, understanding and delivering
language and movement functions. The forebrain comprises of various parts such as the
thalamus, cerebral cortex, the hypothalamus, and cerebrum.
Interneurons go about as couriers that relate motions among motor and sensory neurons.
The procedure of integration is the handling of the different sensory signals that are passed into
the CNS at some random time. These signs are assessed, evaluated and acted upon for decision
making. Besides, those not utilized are either discarded or stored for memory as deemed relevant
or fit by the system. This happens in the gray matter of the brain and spinal cord and is
performed by interneurons. Numerous interneurons cooperate to shape complex networks that
give this preparing power.
Movement Control
Hampel, Franconville, Simpson & Seeds (2015) explains the various kinds of body
movement are realized by the symphonic contraction and relaxation of body muscles. In this
case, the issues of contraction take place when the nerve impulses are transmitted through
neuromuscular intersections to the membrane covering each muscle fiber. Most muscles are not
perpetually contracting but instead, are kept in a state prepared to contract in case it is needed —
the scarcest movement or even the intention to move results in the extensive activity of the
muscles of the limbs and trunk.
NEURON CONTROL OF MOVEMENTS
7
Motor activities in human might be intrinsic to the body itself and completed by muscles
of the trunk and body cavity (Hampel, Franconville, Simpson & Seeds, 2015). Examples are
those associated with swallowing food items, breathing, urinating, laughing, sneezing and other
myriads activities. Such movements are to a great extent done by smooth muscles of the viscera
such as bladder and alimentary canal; these parts are innervated by parasympathetic nerves,
efferent, and sympathetic nerves. Different kind of motor activities relate the body to the
prevailing environment, and the functions are either, either for body movement or for signaling
to other people. These are completed by the skeletal muscles of the trunk and limbs. The skeletal
muscles are attached to the bones and deliver the required movement at the joints. Efferent
movement nerves innervate them and in some cases by parasympathetic nerves and efferent
sympathetic (Enoka, 2015; Bourane et al., 2015).
Each movement of the body must be inappropriate act speed, force, and the position.
These parts of the movement are consistently answered to the central nervous system through
various receptors sensitive to the equilibrium of the region to be moved or put in motion, posture
and position, and inner states of the body. These receptors are called proprioceptors, and those
keep on moving continuous evaluation of the situation of the tendon organs limbs are and muscle
spindles Bourane et al., 2015).
Bourane et al., (2015) further add that movement can be sorted out at a few dimensions of
the nervous system. At the lower level dimension includes the movement of the viscera, some of
which does not incorporate the nervous system, being controlled by neurons of the autonomic
sensory system inside the Viscera themselves. Trunk and Limbs movement takes place at the
next dimension of the spinal cord. In case the spinal cord is severed with the goal that no nerve
NEURON CONTROL OF MOVEMENTS
8
impulses land from the Brain, a certain movement of the trunk and limbs underneath the
dimension of the damage can in any case occur. At a higher level, the respiratory movements are
controlled by the lower brainstem. The upper brainstem engaged in the regulation of muscles of
the eye, the bladder, and fundamental level of movement such as walking and running. The
following dimension is the hypothalamus, and its roles include directing specific functions in
totalities of movement. For example includes activities such as curling up, urinating, vomiting
and defecating, and nodding off among others. At the most elevated amount is a gray matter of
the cerebral hemispheres, subcortical basal ganglia, and the cortex. This is the dimension of
conscious control of movements (Kelso, 2014).
Tactile Receptors
Only a minority of the nerve fibers providing a muscle are customary motor fibers that
make it contract. The rest are either afferent sensory fibers that inform the central nervous system
what the muscle is doing or concentrated motor fibers controlling the behavior of the sensory
nerve endings. In cases the constant input of proprioceptive data from the tendons, muscles, and
joints is cut off, movements can, in any case, happen, however, they cannot be adjusted to suit
changing conditions; nor can new motor skills be produced. As expressed over, the sensory
receptors mainly take concern of the body movement t includes the muscle spindles and tendon
organs. The Muscle Spindle is immensely more complex than the tendon organ, so that, even
though it has been considerably more intensively examined, it is less known or understood
(Schwarz, 2016).
Ligament Organs
The tendon organ comprises mainly of an afferent nerve fiber that ends in various
muscles of the tendon where the tendons join onto muscle fibers. By lying in tandem with
NEURON CONTROL OF MOVEMENTS
9
muscle, the tendon organ is very much set to flag any muscular tension. Indeed, the afferent fiber
of the ligament organ is sufficiently delicate to produce a valuable flag on the contraction of a
single muscle fiber. Along these lines, ligament organs give a continuous stream of data on the
dimension of muscular withdrawal (Schwarz, 2016).
Muscle Axles
According to Heiney, Kim, Augustine & Medina (2014), the natural Knee-Jerk reflex,
tried routinely by physicians, is a spinal reflex in which a short, express tap on the knee
energizes muscle spindle afferent neurons, which at that point stimulate the motor neurons of the
extended muscle through a solitary synapse in the spinal cord. In this direct reflexes, which is not
transmitted through interneurons of the Central Nervous System, the deferral time is around 0.02
second and mostly happens in the conduction of impulses to and from the spinal string.
Knee-jerk reflex and motor-neuron connection
The Cerebral Cortex and cerebellum additionally use data given by muscle spindles in
manners that keep on focusing on nitty-gritty evaluation. One perfect example includes
kinesthesia or the subjective sensory awareness of the situation of limbs in space. It may be
assumed that sensory receptors in joints, not the muscles, give Kinesthetic signs since individuals
are incredibly concerned of joint angle and not in any manner of the length of the different
NEURON CONTROL OF MOVEMENTS
10
muscles included. The fact is that kinesthesia largely depends to a great extent upon the
integration inside the cerebral cortex of signs from the muscle spindles (Heiney, Kim, Augustine
& Medina, 2014).
The main question is tell me how we decide to transfer between walking and running.
Scientists have taken a step closer towards understanding what happens in the brain when we
begin to run or walk. According to Schwarz (2016), the two parts of the midbrain transmits
signals to the spinal cord, and this is passed over to the legs informing it when it should begin
moving and also how slow or fast this needs to happen. In this regard to the literature explored
above the difference between walking and running is only the speed and the signals are sent from
the brain. So when we begin to move, the brain gives the signal through the spinal cord which is
then passed to the nerve cells to control the precise movement of the muscles. Besides, both are
running and walking are not controlled from the same point but different parts of the brainstem
control specific aspects of moving.
Conclusion
Motor Neurons are among the most critical neurons in the central nervous system and
have long axons that make a trip along peripheral nerves to innervate skeletal muscles. They are
the last primary pathway through which the brain controls real movement made by human
beings. Motor neurons get excitatory and inhibitory synaptic contributions from sensory afferents
and pathways. The inherent properties of these neurons decide how these information sources are
transformed into a grouping of action potentials that inspire muscle compression, contraction
with an objective of initiating movement. Motor neurons are enlisted in manners that make
effective utilization of the muscle fibers they innervate. Every single movement activity –
NEURON CONTROL OF MOVEMENTS
regardless of whether stereotyped is extraordinarily determined by a grouping of muscle
contraction.
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NEURON CONTROL OF MOVEMENTS
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