The brain is an organ about which we currently know only a fraction of its full functionality. Yet, it plays a central role in the performance of our body, our behavior, and our inner life. At Dendron, we are on a mission to bring part of this knowledge to the people, helping them better understand themselves in this area and providing them with a tool to manage stress and anxiety. In this blog, our goal is to make this fascinating field more accessible to those interested, and we will kick it off with a series of introductory articles on the processes and technology that allow us to obtain information from the brain and apply it to improve our well-being. To do so, we will focus on one of the most well-known activity patterns: the alpha rhythm.
So, how can we extract information from the brain? The primary cells that make it up, called neurons, communicate with each other through chemical and electrical processes. The electrical activity of large groups of neurons, particularly in the outer part of the brain (which we call the cerebral cortex), can be measured by placing a series of electrodes on a person’s scalp. Today, this neuroimaging technique is known as electroencephalography (EEG). The aforementioned neuronal activity produces an oscillatory signal, which is why different oscillation patterns are identified. These patterns are distinguished by the speed of their cycles, measured in hertz (Hz), which represents the number of oscillations per second.
Among these oscillatory patterns, or neural rhythms, the alpha rhythm was the first to be observed by Hans Berger in 19291. Although he described it in different terms, today we identify the alpha rhythm as an oscillation between 8 and 13 hertz2. The most well-known expression of the alpha rhythm is observed in the posterior part of the brain when a person has their eyes closed. Upon opening their eyes, the alpha rhythm disappears, a phenomenon known as ‘alpha blocking’. Alpha blocking in response to visual stimulation is highly consistent, and it can also occur—though more variably—in response to other stimuli, such as auditory stimulation or the performance of complex mental tasks, such as mental arithmetic problems. Studies from the 1990s found that alpha blocking triggered by this latter phenomenon seemed to depend on factors such as a person’s motivation to perform well in experimental tasks. Researchers hypothesized that the inconsistency in alpha blocking might stem from the fact that these mental tasks rely on complex cognitive functions, which different individuals may solve in different ways. From these notions and later studies, the alpha rhythm is typically associated with a state of relaxation, where the brain is not engaged in any specific mental activity.
Our understanding of the alpha rhythm has led to the development of neurofeedback therapies3, which allow users to voluntarily increase their alpha rhythm, thereby achieving deeper relaxation states or even enhancing cognitive abilities. Crucially, an increase in alpha rhythm can indicate a state of meditation, as well as aid in the reduction of adverse psychological states such as anxiety. This last application strongly resonates with our mission at Dendron: to provide a means of understanding mental activity and improving the well-being of our clients, giving users the tools to take control and work on their inner world. Of course, many other indicators of brain activity exist beyond the alpha rhythm, including other classic brain rhythms. The knowledge and effort required to measure brain activity, identify it precisely, and turn it into a useful measure for personal development are vast. Today, we are witnessing a true explosion in the accessibility of this fascinating area of neuroscience for anyone who wants to benefit from it.
References
[1] Buzsaki, G. (2006). Rhythms of the Brain. Oxford university press.[2] Niedermeyer, E. (1997). Alpha rhythms as physiological and abnormal phenomena.International journal of psychophysiology, 26(1-3), 31-49.
[3] Difrancesco, M. W., Holland, S. K., & Szaflarski, J. P. (2008). Simultaneous EEG/functional magnetic resonance imaging at 4 Tesla: correlates of brain activity to Footnotes spontaneous alpha rhythm during relaxation. Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society, 25(5), 255–264.
[4] Lestari, F. P. A., Pane, E. S., Suprapto, Y. K., & Purnomo, M. H. (2018, March). Wavelet based-analysis of alpha rhythm on eeg signal. In 2018 International Conference on Information and Communications Technology (ICOIACT) (pp. 719-723). IEEE.
[5] Marzbani, H., Marateb, H. R., & Mansourian, M. (2016). Neurofeedback: A Comprehensive Review on System Design, Methodology and Clinical Applications. Basic and clinical neuroscience, 7(2), 143–158.
[6] Vernon, D., Dempster, T., Bazanova, O., Rutterford, N., Pasqualini, M., & Andersen, S. (2009). Alpha neurofeedback training for performance enhancement: reviewing the methodology. Journal of neurotherapy, 13(4), 214-227.
Footnotes
- As a curious fact, Berger conducted his highly exhaustive studies on human brain activity driven by a strong interest in proving a scientific basis for telepathy—how one brain could directly receive activity from another without the intervention of the usual sensory channels.
- This frequency range is not strict, and different sources may slightly vary in defining the exact boundaries of brain frequency bands. Today, we know that there are slight individual differences in these patterns of brain activity.
- Neurofeedback consists of the real-time measurement of brain activity with the goal of presenting it to the user in a sensory format (e.g., visual or auditory), thereby facilitating training in modulating the target brain activity.