The Communicating Brain: Clapping “the Wave”
Itravel to New York often, and I love going to see Broadway musicals. When The Book of Mormon opened, I was one of the first to buy tickets. Members of the audience were laughing all the way through. At the end, the cast got a standing ovation.
Suddenly, the applause changed. Rather than a thousand people clapping separately, everyone began to clap in rhythm. Clap, clap, clap, clap. The rhythmic clapping become so insistent that the actors came back onstage for an encore. The clapping communicated approval to the actors, and they responded with another song.
The neurons in your brain do something similar. They fire together in rhythmic patterns, communicating with each other across the brain. These patterns are measured in cycles per second, or Hertz (Hz). Imagine an audience clapping together slowly. That’s a slow brain wave, with millions of neurons firing together slowly. Imagine an audience clapping quickly. That’s a fast brain wave, with millions of neurons firing together quickly.
Today’s EEGs calculate brain wave patterns from each of the brain’s many different parts. They typically use 19 electrodes attached to the surface of the scalp.
One research team observed, “Scientists are now so accustomed to these EEG correlations with brain state that they may forget just how remarkable they are…. A single electrode provides estimates of synaptic action averaged over tissue masses containing between roughly 100 million and 1 billion neurons” (Nunez & Srinivasan, 2006). When we see brain wave changes on an EEG, it indicates that the firing patterns of billions of neurons in our brains are also changing.
What Brain Waves Are and What They Do
There are five basic brain waves that are picked up by a modern EEG.
1. Gamma Brain Waves
Gamma is the highest brain wave frequency (40 to 100 Hz). It’s most prevalent at times when the brain is learning, making associations between phenomena and integrating information from many different parts of the brain.
A brain producing lots of gamma waves reflects complex neural organization and heightened awareness. When monks were asked to meditate on compassion, large flares of gamma were found in their brains (Davidson & Lutz, 2008).
They were compared to novice meditators who had meditated for an hour a day the week before. The novices had brain activity similar to that of the monks. But when the monks were instructed to evoke a feeling of compassion, their brains began to fire in rhythmic coherence, like the audience clapping at The Book of Mormon musical.
The flares of gamma waves measured in the brains of the monks were the largest ever recorded. The monks reported entering a state of bliss. Gamma is associated with very high levels of intellectual function, creativity, integration, peak states, and of feeling “in the zone.” Gamma waves flow from the front to the back of the brain about 40 times per second (Llinás, 2014). Researchers look to this oscillating wave as a neural correlate of consciousness (NCC), a state linking the brain’s activity with the subjective experience of consciousness (Tononi & Koch, 2015).
Brain researchers talk about the amplitude of a brain wave and that simply means how big it is. A high amplitude of gamma means a big gamma wave, while a low amplitude means a small one. Measurements of brain waves show peaks and valleys. The distance from the peak to the trough is the amplitude. Amplitude is measured in microvolts, and brain waves typically measure between 10 and 100 microvolts, with the faster waves like gamma having the lowest amplitude.
Gamma brain wave states are associated with many beneficial changes in our bodies. A frequency of 75 Hz is epigenetic, triggering the genes that produce anti-inflammatory proteins in the body (De Girolamo et al., 2013). On the lower end of the gamma spectrum, a frequency of 50 Hz results in the body increasing its production of stem cells, the “blank” cells that differentiate into muscle, bone, skin, or whatever other specialized cells are required (Ardeshirylajimi & Soleimani, 2015). The frequency of 60 Hz regulates the expression of stress genes, those that code for stress hormones like cortisol. The same brain wave frequency also activates a key gene called Myc that in turn regulates around 15 percent of all the other genes in the body (Lin, Goodman, & Shirley‐Henderson, 1994).
EEG brain waves from slowest to fastest.
2. Beta Brain Waves
The next fastest wave is beta (12 to 40 Hz). Beta is typically divided into two parts: high beta and low beta. High beta is your monkey mind. High beta (15 to 40 Hz) is the signature brain wave of people with anxiety, people experiencing frustration, and people under stress.
The more stressed people become, the higher the amplitude of the beta their brains produce. Negative emotions such as anger, fear, blame, guilt, and shame produce large flares of beta waves in the EEG readout.
This shuts down the brain regions that handle rational thinking, decision making, memory, and objective evaluation (LeDoux, 2002). Blood flow to the prefrontal cortex, the “thinking brain,” is reduced by up to 80 percent. Starved of oxygen and nutrients, our brains’ ability to think clearly plummets.
Low beta is the band that synchronizes our bodies’ automatic functions, so it’s also called the sensorimotor rhythm frequency, or SMR (12 to 15 Hz).
Beta is required for processing information and for linear thinking, so normal levels of beta brain wave states are fine.