Where Life Meets Technology - The Science of BCIs
- Rohan Naidoo
- Jul 30
- 11 min read
Neurological diseases & conditions are vast & severe, affecting those who have been victims of injury, infection, genetic degeneration & heritability, structural defects, tumors & even restricted blood flow to the brain, caused by environmental, lifestyle & even genetic factors. Neurological conditions can vary from multiple sclerosis to even depression, highlighting the interconnection between tangible & intangible stimuli/responses & how they work together to enable survival as a human species. With "physical" neurological conditions, often muscle rigidity & wastage, loss of sensation, structural defects & even immobility of parts of the body can develop, as nerve cells & the medium for communication & response to stimuli & each other significantly hinder one's ability to live comfortably & optimally. However, new & cutting edge advancements in medicine & technology have revealed that this no longer has to be the case. While one may lose their ability to speak or move, there is no saying that one cannot have the ability to move & speak via technology & machinery. Technology has now become an integral part of the 21st Century & has now integrated itself into the very devices that can allow those to speak, move & feel once more. Muscles & nerves are bypassed. In this article, we will be taking a quick dive into the structural components of the nervous system & how this relates to neurological disorders, diseases & conditions, in addition to how underlying issues can be prevented with the Brain-Computer Interface.
What is the Brain-Computer Interface?
Simply put, a brain-computer interface is the result of complex & interconnected engineering that combines hardware & software communication systems that allows for computers & other external devices to be solely controlled & manipulated from cerebral activity. While it has the potential to range from the ability to think & transcribe onto computers without physical interaction, its sole use in the medical field is to enable those & provide communications capabilities for those severely & physically impacted by neurological & neuromuscular disorders, diseases &/or conditions, like a neurovascular accident, amyotrophic lateral sclerosis & conditions related to the injury of the spinal cord.
The Nervous System
The nervous system's primary functional unit is the nerve cell, otherwise known as the neuron. Here, the neuron consists of four key components, the cell body, dendrites, axon & axon terminals. The cell body contains the nucleus & appropriate organelles of the neuron, most noticeably the rough endoplasmic reticulum that produces proteins & amino acids for neurotransmitter production. These neurotransmitters are used to convey electrical impulses & information from one nerve cell to the next.
The dendrites are outgrowths from the cell body that receive these impulses from the environment & surrounding neuronal cells. Similarly, axon terminals are the outgrowths at the outermost distal parts of the neuron that transmit electrical impulses to the dendrites of other cells, often through neurotransmitter release. For this reason, one might find many mitochondria located at & around the axon terminals to allow for active transport & diffusion of neurotransmitters from one cell to the next.
Lastly, the axon can be found between the cell body & its dendrites & the axon terminals of the neuron. It is a long, narrow structure in which nerve impulses are conducted through to reach the axon terminals. In the central nervous system, which we will cover in minute, the axon is covered in a myelin sheath produced by oligodendrocytes, whereas this sheath is produced by Schwann cells in the peripheral nervous system. All axons are "spotted" with Nodes of Ranvier, which are gaps in the myelin covering that allow for less energy to be used as electrical impulses jump over these "deficient" areas. This also allows for the effective & energy/speed-efficient transmissions of information in the nervous system.
It is worthwhile to notice that neurons can differ in their "general structure" depending on the function that they serve within the body, often related to & integrated with the location of these neurons within the body. For example, sensory neurons may be pseudounipolar in structure to allow for efficient receival & transmission of electrical impulses up the spinal cord, to appropriate areas in the brain & back for further transmission to parts of the body.
The Nervous System - Expanded
With prior knowledge in place, the nervous system consists noticeably of the central & peripheral nervous systems, the CNS consisting of the brain & spinal cord & the PNS consisting of all the nerve fibres bundles together (nerves) that branch outwards from the spinal cord & to other parts of the body, like the limbs for example.
Generally speaking, descending tracts & ascending tracts of second-order nerves travel up & down the the intricately constructed layout of the spinal cord & its respective positioning of tracts that allows for sensory information to reach different parts of the brain, including the cerebellum & thalamus, & muscles of the body, located at neuromuscular junctions. These tracts are joined to the peripheral nervous system via dorsal & ventral roots, dorsal roots containing the cell bodies of nerve fibres forming ascending tracts & ventral roots that of the descending tracts. These nerve fibres from the ventral roots then branch outwards to different parts of the body to provide physical sensation & response to stimuli. Meanwhile, first-order nerves forming the dorsal roots "merge" together to synapse with the ascending tracts or "second-order" nerves to allow the brain to perceive & produce response to external stimuli, which are then transmitted via the descending tracts.
Hindrances & Damage to the Nervous System
The nervous system can be damaged in numerous ways, ranging from the cellular level, to as far as the cumulative impact of damaged structures within the Central Nervous System. However, most of these causes can be traced back to genetic, environmental, lifestyle, hormonal & even medicinal factors present within one's life. In this subsection of this article, we will be looking at a very few of the conditions that one can present in acute or chronic neurological conditions, that will help you develop a greater understanding of the macrocosm & interconnected facets of the nervous system & how components of this system affect one another.
At a cellular level, the main pathological factors influencing the development of neurological conditions is the disruption of energy metabolism & the disruption of the functioning of the glutamate-mediated excitatory synaptic response. In many cases, hindrances in energy metabolism is often caused by the dysregulated homeostatic control of calcium, oxidative stress & altered bioenergetics in the mitochondria. In addition, the hindrance of rough endoplasmic reticulum, a lack of blood, oxygen & glucose to the neurons can easily prevent sufficient amounts of adenosine triphosphate (ATP) & glutamate (neurotransmitter) from being produced, which can significantly reduce the ability for electrical impulses to be passed from one neuron to the next.
These conditions of hindered electrical impulse "conductivity" between the neurons, also including the destruction of synapses, axon terminals & dendrites that further hinder conductivity are often caused by increased levels of physical activity, high levels of stress & head injuries/trauma that often result in "cell death" & elevated rates of glutamate production, excessively stimulating & killing neurons. These are often seen in major conditions such as Alzheimer's Disease & Parkinson's Disease.
Demyelination can be caused by infectious diseases & pathogens, altering the functions of the neuronal nucleus. Furthermore, autoimmune diseases can further cause degradation of the "myelin coat" of the neuron, often associating itself with conditions such as Neuromyelitis Optica Spectrum Disorder (NMOSD), in which demyelination damages optic nerves & the spinal cord. Transverse Myelitis causes weakness & sensory change in the limbs, while Acute Disseminated Encephalomyelitis (ADEM) results from viral infections & pathogenic proteins triggering demyelination.
Injuries that sever nerves, damage areas of the brain, in addition to lifestyle factors of excessive exercise, poor diet, heavy stress & even cognitive engagement within one's environment (links to "synaptic pruning") can lead to further neuronal degeneration & lead to the inability for electrical impulses to reach the brain &/or the Peripheral Nervous System (PNS).
The Brain-Computer Interface
From the conditions stated above, life-altering conditions, such as Aphasia & Parkinson's Disease can be alleviated with the newfound help of Brain-Computer Interfaces (BCIs). Using intricate & sensitive components, the BCI can help bypass the structural importance & defects of nerve fibres & tissues & rather provide an external platform for communication & movement, often through robotic limbs & other forms of technology & software.
The Structure & Processes of the Brain-Computer Interface
The typical BCI consists of 5 key components & procedures, including signal acquisition, preprocessing, feature extraction, classification & applications. In the signal acquisition process, brain waves & electrical signals are captures using invasive & non-invasive techniques. In non-invasive techniques, one might expect to find an electroencephalogram being used, in which electrodes are attached to specific areas of the head to detect & transmit brain signals from certain regions of the brain. While this may be safer, more convenient & costly for a patient, additional noise & artifacts will have to be controlled & "filtered" to express the patient's intentions.
On the other hand, invasive techniques involve placing sensors &/or micro/electrodes on the meninges, within the motor cortex for disabled patients, or within other areas of the brain to meet the intentions of the BCI & patient. Very commonly, intracortical recordings will be placed & used within the brain's cortex to effectively & precisely capture the brain signals to communicate sufficiently. This, in a sense could have a BCI with a more enhanced system, as little controls are needed to "filter" out noise & artifacts.
In the preprocessing process, raw brain signals are refined to reduce noise & other foreign artifacts affecting the effectiveness of the BCI output. In this case, Visual Evoked Potentials (VEPs), the varied shifts in electrical activity in the brain with different functions (Slow Cortical Potentials or SCPs), a response to a spontaneous stimulus (P300 Evoked Potential) & Sensorimotor Rhythms (SRs) are used together to understand a patients brain function & response & tailor/engineer the responses of attached soft & hardware.
Feature extraction is essentially the process in which key frequencies associated with certain mental functions are identified for the computer & software components of the BCI to understand & act upon. In this case, Time-Frequency Analysis will often be used to associate certain frequencies with certain tasks, intentions & states of mind over time as the BCI is further developed & tailored to the patient's needs. In addition, signal decomposition & isolation, differentiation of different mental states through EEG data & deeper learning approaches (likely new use of artificial intelligence) can help identify key frequencies that can "activate" systems within the BCI.
Classification branches from Feature Extraction, in which coding & analysis software analyse the refined signals & frequencies which innervate the Applications process of fulfilling a patient's intentions through different hard & software. Consider the visuals below tailored for the "article's" & communicative purposes:
Engineering, Medical & Other Considerations of the BCI
The BCI is beneficial in the sense that it is mostly an "external" procedure, involving little of the nervous system except for the brain. For this reason, those severely affected by neurological disorders may find the use of BCIs life-changing. While this may be the case, BCIs still render themselves costly, intricate & susceptible to health problems & physical effects, including fatigue, headaches, inflammation & infection in the brain tissues & even seisures in conjunction with infection of the brain tissue.
Additionally, coding software & the hardware systems of the Application system would have to be specifically designed to best aid a patient & their brain functions. This would include the design of electrodes & amplifiers, fine-tuning algorithms & ensuring comfort, all while ensuring the individual variabilities of the brain are considered & best accommodated for.
Revolutionising BCIs in the 21st Century
BCIs have proven to significantly alter the quality of life for many, using cutting-edge technology & engineering to ensure the best integration for patients. With further research, the risk of seisures, infection & inflammation are being reduced significantly, while further advancements in the relationship between the brain & technology help further tailor & facilitate experiences & intentions of a patient. In the 21st Century, it would be interesting to see how artificial intelligence is used to enhance the Feature Extraction & Classification processes of each individual patient. Meanwhile, the scope & opportunity for the BCI is vast & astounding, providing a promising future for neurology, neuroscience & the advancement of the human life & what heights & definitions healthcare will reach in the near future.
If you found this article interesting & helpful, be sure to check out the following links:
Brain-Computer Interfaces from a Surgical, Medicinal & Experimental Perspective -
AI & BCIs -
Applications, Revolution & Patient Experiences Relating to the BCI -
Bibliography
Barnes, S. (2019). Ultrastructure of Nerves - Classification - Neurons - TeachMeAnatomy. [online] Teachmeanatomy.info. Available at: https://teachmeanatomy.info/the-basics/ultrastructure/nerves/.
Bath, M. (2015). The Spinal Cord - Meninges - Vasculature - TeachMeAnatomy. [online] Teachmeanatomy.info. Available at: https://teachmeanatomy.info/back/nerves/spinal-cord/.
Calabresi, P., Centonze, D. and Bernardi, G. (2000). Cellular factors controlling neuronal vulnerability in the brain: A lesson from the striatum. Neurology, 55(9), pp.1249–1255. doi:https://doi.org/10.1212/wnl.55.9.1249.
Craven, J. (2011). Major ascending and descending tracts in the spinal cord. Anaesthesia & Intensive Care Medicine, 12(1), pp.26–27. doi:https://doi.org/10.1016/j.mpaic.2010.10.001.
Dock, H. (2024). Understanding Neuro-anatomy A Comprehensive Review. International Journal of Anatomical Variations, [online] 17(5). doi:https://doi.org/10.37532/1308-4038.17(5).396.
Gert Pfurtscheller, Neuper, C. and Niels Birbaumer (2004). Human Brain—Computer Interface. Frontiers in neuroscience. doi:https://doi.org/10.1201/9780203503584.ch14.
Gorman, A.M. (2008). Neuronal cell death in neurodegenerative diseases: recurring themes around protein handling. Journal of Cellular and Molecular Medicine, 12(6a), pp.2263–2280. doi:https://doi.org/10.1111/j.1582-4934.2008.00402.x.
Johns Hopkins Medicine (2019). Overview of Nervous System Disorders. [online] Johns Hopkins Medicine Health Library. Available at: https://www.hopkinsmedicine.org/health/conditions-and-diseases/overview-of-nervous-system-disorders.
Jones, O. (2018). The Ascending Tracts - DCML - Anterolateral - TeachMeAnatomy. [online] Teachmeanatomy.info. Available at: https://teachmeanatomy.info/neuroanatomy/pathways/ascending-tracts-sensory/.
Li, N.Y., Guan, N.C. and Qin, N.J. (2005). Enhancing Feature Extraction with Sparse Component Analysis for Brain-Computer Interface. PubMed, pp.5335–5338. doi:https://doi.org/10.1109/iembs.2005.1615686.
Nicolas-Alonso, L.F. and Gomez-Gil, J. (2012). Brain Computer Interfaces, a Review. Sensors, [online] 12(2), pp.1211–1279. doi:https://doi.org/10.3390/s120201211.
Parkinson, G. (2017). The Grey Matter of the Spinal Cord - TeachMeAnatomy. [online] Teach Me Anatomy. Available at: https://teachmeanatomy.info/neuroanatomy/structures/spinal-cord-grey-matter/.
Physiopedia. (n.d.). Neurological Disorders. [online] Available at: https://www.physio-pedia.com/Neurological_Disorders.
Popoli, M., Yan, Z., McEwen, B.S. and Sanacora, G. (2011). The stressed synapse: the impact of stress and glucocorticoids on glutamate transmission. Nature Reviews Neuroscience, [online] 13(1), pp.22–37. doi:https://doi.org/10.1038/nrn3138.
Powers, B. (2020). Technology Melds Minds With Machines, and Raises Concerns. [online] Undark Magazine. Available at: https://undark.org/2020/04/22/brain-technology-interface/.
Schmidt, C. (2024). Designing Brain-Computer Interfaces That Connect Neurons to the Digital World. [online] Harvard.edu. Available at: https://magazine.hms.harvard.edu/articles/designing-brain-computer-interfaces-connect-neurons-digital-world.
Shamari, A. and O’Hara, L. (2024). ‘I am not the same as before’: a mixed-methods study on depression in people with spinal injury in Qatar. Frontiers in Psychiatry, [online] 15. doi:https://doi.org/10.3389/fpsyt.2024.1288772.
Shih, J.J., Krusienski, D.J. and Wolpaw, J.R. (2012). Brain-Computer Interfaces in Medicine. Mayo Clinic Proceedings, [online] 87(3), pp.268–279. doi:https://doi.org/10.1016/j.mayocp.2011.12.008.
Šimić, G., Tkalčić, M., Vukić, V., Mulc, D., Španić, E., Šagud, M., Olucha-Bordonau, F.E., Vukšić, M. and R. Hof, P. (2021). Understanding Emotions: Origins and Roles of the Amygdala. Biomolecules, [online] 11(6), p.823. doi:https://doi.org/10.3390/biom11060823.
Thau, L., Reddy, V. and Singh, P. (2022). Anatomy, Central Nervous System. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK542179/?report=printable [Accessed 23 May 2025].
Thorbecke, C., Sealy, A. and Kounang, N. (2024). This ALS patient has a brain implant that translates his thoughts to computer commands. [online] CNN. Available at: https://edition.cnn.com/2024/02/28/tech/brain-implant-als-patient-bci [Accessed 26 Jun. 2025].
UFO Themes (2016). Nervous tissues. [online] Basicmedical Key. Available at: https://basicmedicalkey.com/nervous-tissues/ [Accessed 24 Jun. 2025].
Waxenbaum, J.A., Reddy, V. and Varacallo, M.A. (2023). Anatomy, Autonomic Nervous System. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK539845/?report=printable [Accessed 23 May 2025].
Zanderlabs.com. (2024). Passive BCIs: Key to AI Potential | Zander Labs. [online] Available at: https://www.zanderlabs.com/blog/passive-bcis-key-to-ai-potential [Accessed 26 Jun. 2025].
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