Science of Falling

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Which Parts of the Brain Are Responsible for Balance and Equilibrium?

You may not think about it as you walk down the street or stand on one leg during yoga, but maintaining your balance is an incredible feat of coordination, handled seamlessly by your brain. The way the brain manages to keep us upright and steady, even when we’re not consciously thinking about it, is truly incredible. But how does it do this? The answer lies in a complex network of brain regions working together like a well oiled machine, constantly processing signals from your body and the world around you.

In this article, we'll explore the fascinating science behind balance and equilibrium, focusing on the brain anatomy responsible for this impressive human skill. Whether you’re walking, running, or simply standing still, these brain areas work overtime to keep you stable. So, let's dive into the inner workings of the brain to uncover how we stay balanced.

The Vestibular System: The Core of Balance

When it comes to balance, the vestibular system in your inner ear is the star player. This system acts like the body’s internal gyroscope, constantly sensing changes in head position and motion, and providing critical information to your brain to keep you upright. (1)

How Does the Vestibular System Work?

The vestibular system consists of five sensory organs located in each ear (1):

  • Three semicircular canals that detect rotational movements (like turning your head).

  • Two otolith organs (the utricle and saccule) that sense linear movements, such as moving forward or backward and the effect of gravity.

These sensory organs contain fluid and tiny hair cells that move in response to motion. When you move your head, the fluid inside the semicircular canals shifts, stimulating the hair cells. This movement generates electrical signals that are sent to the brain, letting it know what kind of motion you’re experiencing.

Dive deeper into the vestibular system with these two articles: Vestibular System Anatomy and Vestibular System Physiology

Reflexes That Keep You Stable

Source: https://www.nasafordoctors.co.za/articles.php?cid=9&id=40&aid=351

The vestibular system isn’t just about sensing motion; it also helps coordinate reflexes that stabilize your body. (2) Two key reflexes help keep you balanced:

  • Vestibulo-ocular reflex (VOR): This reflex stabilizes your vision during head movements by keeping your eyes focused on a target. Imagine trying to read a book while shaking your head. Without the VOR, the text would be a blurry unreadable mess.

  • Vestibulo-spinal reflex (VSR): This reflex sends signals from the vestibular system to muscles throughout your body, ensuring you maintain balance when your head moves. For example, if you stumble while walking, this reflex helps your body make rapid adjustments to avoid falling.

While the vestibular system provides critical information about head position and movement, it doesn’t work alone. The brain has to combine this data with other sensory inputs to maintain full-body balance.

The Cerebellum: The Brain’s Internal Balancer

Source: https://www.nasafordoctors.co.za/articles.php?cid=9&id=40&aid=351

Next up in the balance equation is the cerebellum, a small but mighty structure located at the back of your brain. Often called the brain’s "internal balancer," the cerebellum integrates input from the vestibular system, proprioception, and motor commands to fine-tune movements and maintain coordination. (3, 4, 5)

Fine-Tuning Movement

Think of the cerebellum as the brain's quality control center. (3, 4 ,5) When you move, your brain sends motor commands to your muscles. Simultaneously, the cerebellum creates "internal models" to predict what those movements should feel like based on past experiences. If the actual movement doesn’t match up with the predicted one (for instance, if you slip on wet pavement), the cerebellum quickly corrects the error by adjusting muscle activity to save you.

This rapid error correction allows you to maintain balance even when your environment changes unexpectedly. When the cerebellum is damaged or impaired, as seen in conditions like ataxia, people often experience unsteady movements and difficulty coordinating their limbs. (3, 4, 5, 6)

Error Detection and Coordination

One of the cerebellum’s most important jobs is error detection. Whether you're walking a straight line or performing a complex dance move, the cerebellum is constantly checking to make sure your movements are smooth and coordinated. It does this by comparing sensory input with motor output, if there's a mismatch, the cerebellum makes adjustments to keep you stable. (7, 8)

The Brainstem: Rapid Postural Reflexes

Source: https://www.physio-pedia.com/Brainstem

While the cerebellum helps refine movements, the brainstem takes care of many automatic functions necessary for balance. (9, 10) This lower part of the brain serves as a relay station, sending signals from the vestibular system and cerebellum to other parts of the body.

Vestibular Nuclei: The Hub for Balance Signals

Within the brainstem lie the vestibular nuclei, which play a key role in integrating vestibular signals with sensory information from the rest of the body. (9, 11, 12) When the vestibular system detects a shift in head position, it sends signals to these nuclei, which then communicate with motor neurons to initiate postural adjustments. For example, if you lean too far forward, the brainstem’s vestibular nuclei will quickly trigger a reflex that activates muscles in your legs and back to prevent you from falling over. These reflexes are fast and automatic, meaning you don’t have to consciously think about them to stay upright.

You can learn more about a few of these balance reactions in this article: Motor Strategies for Balance Control

Proprioception: Your Body’s Internal GPS

Source: https://www.flintrehab.com/parietal-lobe-damage/

Now, imagine standing with your eyes closed. Even though you can’t see your surroundings, you still know where your arms and legs are in space, thanks to a sense called proprioception. (13) This internal “GPS” relies on sensory receptors in your muscles, joints, and skin that send continuous feedback to your brain about body position.

Integration in the Parietal Cortex

All this proprioceptive information is processed by the parietal cortex, which helps the brain form an accurate map of where your body is in relation to its surroundings. (14, 15) This sensory feedback is crucial for balance because it allows your brain to detect subtle changes in body position, even without visual cues such as at night or in low light conditions.

Proprioceptive Dysfunction and Balance

When proprioception is impaired, your ability to maintain balance can suffer. (16, 17, 18) Conditions that affect proprioception, like neuropathy from diabetes or joint injuries, often result in difficulty controlling movements and a higher risk of falls. By practicing balance exercises, you can help improve proprioception and strengthen the connection between your brain and body.

The Parietal and Frontal Cortices: Higher-Level Control

Source: https://blog.cognifit.com/frontal-lobe/

While the vestibular system, cerebellum, and brainstem handle much of the hard work when it comes to balance, higher-level brain regions also play an important role.

Parietal Cortex: Integrating Sensory Inputs

As mentioned earlier, the parietal cortex integrates sensory information from proprioception, the vestibular system, and vision to create a comprehensive understanding of body position in space. (14, 15) This region is crucial for maintaining balance, particularly in complex environments where multiple sensory cues must be processed simultaneously.

Frontal Cortex: Planning and Anticipation

The frontal cortex is involved in planning movements and making anticipatory adjustments to posture. (19, 20) For example, when you see a crack in the sidewalk ahead, your frontal cortex helps plan a movement to step over it. This part of the brain also plays a role in voluntary motor control, which is essential for maintaining balance during intentional movements.

The Role of Vision in Balance

Source: https://www.mozaweb.com/en/Extra-3D_scenes-The_human_eye-12014

It’s easy to take vision for granted when it comes to balance, but it plays a critical role in keeping us stable. While the vestibular system provides rapid feedback on head position, the visual system gives us essential information about our surroundings, allowing us to orient ourselves in space and know which way is up.

Visual Feedback

The visual system works with the vestibular and proprioceptive systems to maintain stability. For instance, when you stand on a moving bus, your brain uses visual cues to assess how the environment is shifting, while your vestibular system detects the motion of your head. Together, these systems help you adjust your posture to stay balanced.

Relying on Vision for Balance

People who suffer from vestibular dysfunction often rely more heavily on their vision to maintain balance in a process called sensory reweighting. (21, 22) In some cases, closing the eyes or walking in low-light environments can significantly impair balance in individuals with vestibular disorders. This is why balance exercises that incorporate both vision and vestibular inputs are particularly effective for improving stability.

The Basal Ganglia: Fine-Tuning Movements

Source: https://www.flintrehab.com/basal-ganglia-stroke/

The basal ganglia is another brain region that helps fine-tune motor control and postural adjustments. (23) While it’s better known for its role in controlling movement initiation, it also works alongside the cerebellum to regulate smooth, coordinated movements.

Postural Control and Disease

Diseases that affect the basal ganglia, like Parkinson’s disease (PD), often lead to postural instability and difficulty with balance. (23, 24) People with these conditions may experience tremors, slowed movements, and a stooped posture, all of which contribute to balance issues. Since the basal ganglia also helps with movement initiation, those with PD often will “freeze” and be unable to continue moving.

Neuroplasticity: Training the Brain to Improve Balance

One of the most exciting aspects of balance is that you can train it, and your brain will actually change as a result. This concept is called neuroplasticity, which refers to the brain’s ability to reorganize itself by forming new neural connections. (25)

How Balance Training Helps

Balance training strengthens the communication between the vestibular system, proprioception, and the cerebellum. (26, 27, 28) Over time, repeated practice helps your brain become more efficient at processing sensory information and making adjustments to maintain stability.

Practical Exercises for Balance

Incorporating exercises like standing on one leg, using a balance board, tandem walking, or practicing yoga can enhance your brain’s ability to maintain equilibrium. These activities challenge your vestibular system and proprioception in a way that improves coordination, and forces the brain to adapt to changing conditions. Not only does this improve your balance, but it also enhances the brain's capacity to make quick adjustments in real-time, reducing the risk of falls.

Final Thoughts: Balancing Act of the Brain

Your ability to stay upright and steady is a true testament to the brain’s incredible coordination. From the vestibular system in your inner ear to the cerebellum’s fine-tuning of movement, multiple brain areas are constantly at work to ensure you maintain balance and equilibrium. Whether you're standing still, walking, or dancing, your brain is processing an unimaginable amount of sensory information from your body and environment to keep you stable. Balance training is not only beneficial for improving physical stability but also for keeping your brain sharp. By practicing specific exercises that challenge your balance, you can actively train your brain to respond better to shifts in position, reducing your risk of falls as you age.

If you're looking to improve your balance or simply learn more about how your brain helps keep you steady, consider incorporating balance exercises into your wellness routine with the Beginner to Intermediate Balance Program. And remember, like any skill, balance can be improved with practice, so keep challenging yourself to stand strong, both physically and mentally.


References

  1. Herdman SJ, Clendaniel R. Vestibular rehabilitation. F.A. Davis; 2014.

  2. Edwards C, Franklin E. Vestibular rehabilitation. StatPearls - NCBI Bookshelf. Published May 23, 2023. https://www.ncbi.nlm.nih.gov/books/NBK572153/

  3. Jimsheleishvili S, Dididze M. Neuroanatomy, cerebellum. StatPearls - NCBI Bookshelf. Published July 24, 2023. https://www.ncbi.nlm.nih.gov/books/NBK538167/

  4. Yoo H, Mihaila DM. Neuroanatomy, vestibular pathways. StatPearls - NCBI Bookshelf. Published November 7, 2022. https://www.ncbi.nlm.nih.gov/books/NBK557380/

  5. Professional CCM. Cerebellum. Cleveland Clinic. Published May 1, 2024. https://my.clevelandclinic.org/health/body/23418-cerebellum

  6. Ataxia and cerebellar or spinocerebellar degeneration. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/ataxia-and-cerebellar-or-spinocerebellar-degeneration

  7. Manto M, Bower JM, Conforto AB, et al. Consensus Paper: Roles of the Cerebellum in Motor Control—The Diversity of Ideas on Cerebellar Involvement in Movement. The Cerebellum. 2011;11(2):457-487. doi:10.1007/s12311-011-0331-9

  8. Andre P, Cantore N, Lucibello L, et al. The cerebellum monitors errors and entrains executive networks. Brain Research. 2023;1826:148730. doi:10.1016/j.brainres.2023.148730

  9. Basinger H, Hogg JP. Neuroanatomy, brainstem. StatPearls - NCBI Bookshelf. Published July 4, 2023. https://www.ncbi.nlm.nih.gov/books/NBK544297/

  10. Professional CCM. Brainstem. Cleveland Clinic. Published July 2, 2024. https://my.clevelandclinic.org/health/body/21598-brainstem

  11. Hernandez E, Das JM. Neuroanatomy, nucleus vestibular. StatPearls - NCBI Bookshelf. Published October 17, 2022. https://www.ncbi.nlm.nih.gov/books/NBK562261/#:~:text=The%20major%20vestibular%20nuclei%20are,or%20Rhomencephalon%2C%20Dorsal%20View).

  12. Purves D, Augustine GJ, Fitzpatrick D, et al. Central vestibular pathways: eye, head, and body reflexes. Neuroscience - NCBI Bookshelf. Published 2001. https://www.ncbi.nlm.nih.gov/books/NBK10987/

  13. Proske U, Gandevia SC. The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force. Physiological Reviews. 2012;92(4):1651-1697. doi:10.1152/physrev.00048.2011

  14. Javed K, Reddy V, Lui F. Neuroanatomy, cerebral cortex. StatPearls - NCBI Bookshelf. Published July 25, 2023. https://www.ncbi.nlm.nih.gov/books/NBK537247/#:~:text=The%20parietal%20lobe%20is%20responsible,optic%20ataxia).%5B5%5D

  15. Dieterich M, Brandt T. The parietal lobe and the vestibular system. Handbook of Clinical Neurology. Published online January 1, 2018:119-140. doi:10.1016/b978-0-444-63622-5.00006-1

  16. Goble DJ, Coxon JP, Wenderoth N, Van Impe A, Swinnen SP. Proprioceptive sensibility in the elderly: Degeneration, functional consequences and plastic-adaptive processes. Neuroscience & Biobehavioral Reviews. 2008;33(3):271-278. doi:10.1016/j.neubiorev.2008.08.012

  17. Riandini T, Khoo EYH, Tai BC, et al. Fall risk and balance confidence in patients with diabetic peripheral neuropathy: an observational study. Frontiers in Endocrinology. 2020;11. doi:10.3389/fendo.2020.573804

  18. Jerosch J, Prymka M. Proprioception and joint stability. Knee Surgery Sports Traumatology Arthroscopy. 1996;4(3):171-179. doi:10.1007/bf01577413

  19. Takakusaki K. Functional neuroanatomy for posture and GAIT control. Journal of Movement Disorders. 2017;10(1):1-17. doi:10.14802/jmd.16062

  20. Cavallari P, Bolzoni F, Bruttini C, Esposti R. The organization and control of Intra-Limb anticipatory postural adjustments and their role in movement performance. Frontiers in Human Neuroscience. 2016;10. doi:10.3389/fnhum.2016.00525

  21. Haran FJ, Keshner EA. Sensory reweighting as a method of balance training for labyrinthine loss. Journal of Neurologic Physical Therapy. 2008;32(4):186-191. doi:10.1097/npt.0b013e31818dee39

  22. Nair MA, Mulavara AP, Bloomberg JJ, Sangi-Haghpeykar H, Cohen HS. Visual dependence and spatial orientation in benign paroxysmal positional vertigo. Journal of Vestibular Research. 2018;27(5-6):279-286. doi:10.3233/ves-170623

  23. Young CB, Reddy V, Sonne J. Neuroanatomy, basal ganglia. StatPearls - NCBI Bookshelf. Published July 24, 2023. https://www.ncbi.nlm.nih.gov/books/NBK537141/

  24. Basal ganglia dysfunction: MedlinePlus Medical Encyclopedia. https://medlineplus.gov/ency/article/001069.htm#:~:text=Damage%20to%20the%20basal%20ganglia%20cells%20may,have%20trouble%20starting%2C%20stopping%2C%20or%20sustaining%20movement.

  25. Voss P, Thomas ME, Cisneros-Franco JM, De Villers-Sidani É. Dynamic Brains and the Changing Rules of Neuroplasticity: Implications for learning and recovery. Frontiers in Psychology. 2017;8. doi:10.3389/fpsyg.2017.01657

  26. Wiesmeier IK, Dalin D, Wehrle A, et al. Balance training enhances vestibular function and reduces overactive proprioceptive feedback in elderly. Frontiers in Aging Neuroscience. 2017;9. doi:10.3389/fnagi.2017.00273

  27. Rogge AK, Röder B, Zech A, Hötting K. Exercise-induced neuroplasticity: Balance training increases cortical thickness in visual and vestibular cortical regions. NeuroImage. 2018;179:471-479. doi:10.1016/j.neuroimage.2018.06.065

  28. Kubica J, Szymura J, Domagalik A, et al. Systematic balance exercises influence cortical activation and serum BDNF levels in older adults. Journal of Clinical Medicine. 2019;8(11):1910. doi:10.3390/jcm8111910