The human brain contains approximately 86 billion neurons. These are the bits and pieces that form our thoughts, emotions, memories, or behaviors. In order to do that, they need to communicate, and they do that using electricity and chemical substances. When multiple neurons transmit an electrical signal, this becomes strong enough to be measured even from outside the brain, and that’s what we call a brainwave. Depending on the type of the signal, the brainwaves have different wavelengths. This means that our brainwaves will change according to what we do and feel.
How to Measure Your Brainwaves
As mentioned a bit earlier, when a significant number of neurons are involved in transmitting and processing an electrical signal, this becomes strong enough to be measured from outside the skull. Electroencephalography (EEG) is the technique used to measure these signals. Electrodes are placed on the skull in order to detect these signals, that are amplified and processed. As with any alternating electrical signal, these signals oscillate, repeating at different intervals called frequency. The frequency is measured in Hertz (Hz).
The most accurate EEG is taken with medical-grade equipment, so it will require going to a medic. Luckily there are many devices one can use now at home in order to detect brainwaves, and the prices keep decreasing. You can find all sorts of devices, from headsets (like Muse or MindWave headsets) to DYI kits and guides.
There are six types of brainwaves. Many consider only 5 types, because the first one, as you will see, lacks documentation and if very hard to analyze.
These have frequencies less than 0.5 Hz, and because they are so slow, they are very difficult to measure and analyze. There is a very limited amount of information related to these brainwaves. Scientists believe they are the basic cortical rhythms that underlie our higher brain functions, having a significant role in brain timing.
These are slow brainwaves, with frequencies between 0.5 and 4 Hz, and high amplitude. These are generated during dreamless sleep or very deep meditation. While sleeping, these waves appear during stage 3 and are strongest during stage 4. They are essential for the healing and restorative properties of sleep. It can happen for the brain to produce too many Delta brainwaves during waking hours, a situation associated with ADHD, and learning disabilities. Studies have shown that in ADHD patients, Delta waves increase instead of decreasing when the patient tries to focus.
When the generation of Delta waves increases, our awareness of the surrounding physical world decreases.
Theta brainwaves are a bit faster than delta and have lower amplitude, with frequencies between 4 and 8 Hz (some consider Delta waves ending at 3.5 Hz, and Theta starting from there).
Theta brainwaves occur during sleep and deep meditation. Our senses are disconnected from the external world and focused on the inner signals. We experience these waves right after waking up and even just before falling asleep. We also experience them while daydreaming.
When the brain produces Theta waves, we feel deeply relaxed.
Alpha brainwaves are next, being a bit faster and having lower amplitude than Theta waves. Their frequencies are between 8 and 12 Hz. These are the easiest brainwaves to detect and measure and were the first type discovered by Hans Berger, the inventor of electroencephalography (EEG), in 1924.
Alpha waves symbolize the resting state of the brain, as they are present when the brain is in an idle state, when we are “in the present”, aware, alert but not processing information. Alpha waves are considered the bridging piece between the conscious and the subconscious. We associate alpha waves production to a state of calm and relaxation.
We are very efficient and completing tasks or at learning new things that we are being taught by somebody else.
Beta brainwaves are even faster, with frequencies between 12.5 and 30 Hz. These were also discovered by Hans Berger, and are associated with active thinking and concentration. These ate considered the normal brain rhythm for people with eyes opened, and alert or anxious. They are present when we are solving problems, judging, processing information, or making decisions.
If you compare the width of the bands, you quickly notice that the Beta band is much wider than the previous bands. Scientists have divided it into 3 narrower segments: low, mid, and high:
- Low Beta (12.5 – 15 Hz): a relaxed and yet focused state.
- Mid Beta (15 – 22 Hz): highly engaged, trying to figure something out.
- High Beta (22 – 30 Hz): very complex thoughts, high anxiety or excitement.
When the brain functions at high frequencies, it consumes a significant amount of energy, so this is not a state it is supposed to be in for extended periods of time. The brain enters these states when needed, and will try to slow down as soon as it can.
And the highest measurable frequency waves are next, beginning at 30 Hz. Gamma brainwaves are linked to heightened perception or peak concentration when the brain needs to simultaneously process information from different areas.
A 2017 study conducted by scientists from France, USA and India found proof that daily meditation practice leads to increased gamma brainwave amplitude 1)Claire Braboszcz, B. Rael Cahn, Jonathan Levy, Manuel Fernandez, Arnaud Delorme – Increased Gamma Brainwave Amplitude Compared to Control in Three Different Meditation Traditions. They analyzed a group of subjects that practiced three different meditation techniques: Vipassana, Himalayan Yoga, and Isha Shoonya. “All meditators showed higher parieto-occipital 60–110 Hz gamma amplitude than control subjects as a trait effect observed during meditation and when considering meditation and instructed mind-wandering (IMW) periods together.”
The table below offers a quick overview of the brainwave types:
|<= 0.5 Hz||Infra-Low||basic cortical rhythms that underlie|
our higher brain functions
|0.5 – 4 Hz||Delta||dreamless sleep or very deep meditation|
|4 – 8 Hz||Theta||daydreaming, sleep, and deep meditation|
|9 – 12 Hz||Alpha||resting brain state, aware, alert but not processing information|
|12.5 – 30 Hz||Beta||problem-solving, processing information, or making decisions|
|> 30 Hz||Gamma||heightened perception or peak concentration|
Can You Train Your Brain to Generate Certain Brainwaves?
As you saw in the Gamma brainwaves description, there are studies showing that daily mediation practice leads to improved Gamma waves.
Probably the most common method for learning to control the brain function is called neurofeedback. It uses sensors placed on the scalp to detect brainwaves and provide visual or audio feedback to the user. This can be accomplished in clinical environments, with sophisticated equipment, but also at home with DIY equipment or freely available gadgets.
There is a strong online community centered around DIY neurofeedback devices. If you are not inclined towards building your own device, there are multiple kits available, like Muse or MindWave Mobile.
There is a lot of controversy regarding the efficiency of neurofeedback training, and I will not go into details. I believe that just like with any other training, you will progress and you will gain more control over your brain. The brain is like a muscle, and we need to keep exercising in order to maintain it healthy and at high working capacity. Neurofeedback devices help you understand what is actually happening with your brain when you do certain things with your mind. This is really helpful, especially at the beginning – in time you will learn how it works and you will be able to train even without a device. If you have ever tried to meditate, you know what I’m talking about: your mind will sometimes do stuff on its own, and it takes a lot of time and practice to learn to tame it.
Scientists still have a lot to uncover about brain activity and brainwaves’ roles, and I’m excited about that the future will bring in this regard.
|↑1||Claire Braboszcz, B. Rael Cahn, Jonathan Levy, Manuel Fernandez, Arnaud Delorme – Increased Gamma Brainwave Amplitude Compared to Control in Three Different Meditation Traditions|