The three brains in your head

Hello and welcome to the first article of my neuro blog. Since 2013, I have become increasingly interested in what neuroscience, the scientific, multi-disciplinary, study of the nervous system can teach us about the brain. My assumption was that understanding the brain would in turn illuminate my comprehension of the mind. The two are definitely "correlated" (I can’t escape my financial past!) but they are not the same. I expect I’ll return to that difference in future posts.

With this neuro blog, I mean to share some of what I’ve discovered about the brain and the insights about the mind which learning about the brain has made possible for me. Having an appreciation for how the brain works has helped me manage my thoughts – to cope with the less helpful ones, my emotions – to move away from the uncomfortable ones, and my behaviour – to choose more how I act.

Let’s start with a quick description of the brain (see insert). As I hinted in this post’s title, we have three brains in our head. From an evolutionary perspective, it starts with the brain stem – that’s the part of the brain which remains alive when you are ‘brain dead’. It manages ten autonomous functions, such as your heart beat, your breathing, your digestion (which starts with salivation), eye pupil dilatation, urination and… sexual arousal. This very old part of your brain is completely unconscious, completely inaccessible to you. But it reacts. It’s called the ‘lizard brain’ and consider what you know of lizards: when they’re afraid, what do they do? Flee, freeze? Sometimes a big lizard may fight back. This part of the brain is all instinctual.

The second brain – called the limbic system – we share with all fellow mammals on Earth and it is the seat of our emotions. It is also completely unconscious. Will you be surprised if I tell you that brain takes a lot of decisions? Anyone who has engaged in impulse buying will know what I mean.

Last but by no means least is the neocortex, that part of our brain where our consciousness lies (but that part is a very small component of the neocortex). This is where we reason, consider abstract concepts, refrain our impulses, make different kinds of decisions and engage in language.

So what? Most of what’s going in our brain is unconscious: as such, the thoughts we think are just the tip of the iceberg. Most of what we do is governed by unconscious processes which are completely inaccessible to us. We are not as much in control as we thought we were. We are ruled by what the neuroscientist David Eagleman calls "zombie systems". Do you find this thought sobering? I certainly did. But I also felt relief: appreciating that my behaviour was in large part the result of unconscious processes helped make sense of actions I didn’t always understand – such as: why are there days when I give in to my chocolate cravings or others where I easily ignore "the call of the chocolate"…?

If you’d like to tell me about your behaviour and/or your brain, you will find me at In the meantime, relax and let your brain look after you!

Print Friendly, PDF & Email

Speak Your Mind