On the Same Brain Wavelength
Brain Wave Synchronisation in Social Species
Hey Rewirers,
Welcome to this week’s newsletter! Did you know that our brain waves synchronize when we interact with others? Read on to find out more.
Brain Waves
We talked about neurons in a previous newsletter, and I mentioned that their axon (see figure below) is used to send signals.
Well, these signals are actually electrical activity. When a lot of neurons send signals at the same time it creates a wave of electrical activity. This mass of electrical signalling can be recorded on electroencephalograms (EEGs) and creates a wave-like pattern, hence, brainwaves (see figure below).
Different types of brainwaves represent different brain states1. We talked about this briefly in regards to sleep states and the importance of avoiding your phone in the morning. Delta waves are the lowest frequency brainwave and these occur during deep sleep. Theta waves are a bit faster, but they’re associated with ‘slow’ behaviour – meditation, prayer, creativity, and daydreaming. Alpha waves are faster again, and these are seen when we’re alert but relaxed. Beta waves are even faster, and these occur when we’re problem-solving or anxious. Finally, gamma waves occur when we’re consolidating information – these waves are important for memory.
Brain Wave Synchronisation
So what’s all this about our brain waves synchronizing? Well, research shows that our brainwaves synchronise when we’re performing synchronized tasks2, like guitar playing3 or gesture imitating4.
Brainwaves also synchronise between people engaging in cooperative social behavior, like building5 or piloting6. There are a few theories as to why this could be. Brainwave synchronization makes us feel more connected and leads to more cooperation. Couples with brainwave synchronisation have greater marital happiness than those without7. This could explain why we feel like we ‘click’ with some people but not with others. In another study, researchers could predict how cooperative social behaviour would be between two people based on their brainwave synchronisation8.
This may help to explain why social isolation can be so harmful to our mental health. We are a social species; the COVID-19 pandemic highlighted this well. The biggest predictor for depression, anxiety, and PTSD in the initial stages of the pandemic was social isolation and loneliness9. Additionally, we know that social isolation increases the risk of death, heart disease, stroke, and dementia10. Social interaction appears engrained in our biology. Â
In fact, we’re not the only social species that brain wave synchronization can be found in. When bats socially interact, their neural activity synchronizes and this can predict current social behavior and future social behaviour11. The same is observed in mice; social interaction leads to interbrain synchronisation and can predict future social decisions12.
But how is this synchronisation happening? I hear you, I do. I’m getting there.
Mirror Neurons
We’re going to take a quick side step to talk about mirror neurons as they bear a striking resemblance to what’s going on in the above studies. Mirror neurons fire when someone performs an action OR when they witness that action being performed by someone else13.  They were originally discovered in monkeys performing motor tasks in 199214, and their equivalent has now been found in several species, including humans, and various brain areas (including motor, sensory, and emotional areas)15.
There is still debate about their exact relevance, but since they fire both when we perform behaviors and we watch other people perform those same behaviours, it is thought that they underly a neural mechanism for ‘inner imitation’ of other people’s behaviour. The initial hype surrounding them has died down as it now appears that they don’t play a role in interpreting actions16, but mainly play a role in discriminating actions. However, their function as an imitation mechanism likely contributes to our social and emotional systems, helping us to display empathy and learn social behaviours17. Â
This role in social interaction, to be able to imitate others within our own neurons, sounds very similar to brain synchronisation, right? Well, recent research expands on this theory!
Self- and Other- Neurons
A recent study on mice12 identified two subgroups of neurons, titled ‘self’ neurons and ‘other’ neurons in the medial prefrontal cortex, which became active when either the mouse itself completed an action or when the second mouse performed an action. Thus, one group records information about what oneself is doing while the other group encodes information about what the other animal is doing. When ‘other’ neurons were blocked, brain synchronisation was significantly reduced. Therefore, brain synchronization requires the recognition of what you are doing and what your partner is doing. This makes sense from a social perspective, as all social interactions require the delicate balance of reading others behaviour and controlling our own behaviour. Although further research is necessary, perhaps mirror neurons play a role in this process as well.
Until next week,
Nicole x
P.S. Leave a comment with topics you want to see in future newsletters!
References
Love your substack and the book. I got the book on Audible when it was first released. You mention the bonus PDF several time in the book but it wasn’t included in my Audible. I’m wondering if it was because I got the book so early. Has anyone else had this issue? Any suggestions on how to get the pdf?