Brain science – the facts
Why bother with brain science?
Knowing how something works, and how it malfunctions, informs us about how to get around a problem. The working of the brain is of course complex, but we know a lot about it, and research with experienced meditators has shown incredible results. When Matthieu Ricard (a French Buddhist monk) was given MRI scans by cognitive scientists, he showed ‘extraordinarily high levels of upbeat activity and almost invisible levels of negative emotions’, giving him his popular attribution as the ‘happiest man on earth’.
The good news from this research is neuroplasticity; the term which describes the brain’s capacity to adapt, re-learn, create new habits, and as a consequence change our interpretation of life around us and our behaviour.
As Hanson and Mendius put it: ‘When your mind changes, your brain changes’; for example, taxi drivers develop a larger hippocampus (the visual-spatial memory area).
The brain contains about 1 trillion cells, 100 billion neurons, and each neuron has about 5000 synapses or connections. These neurons communicate, relaying messages, creating pathways of connectivity. As these pathways get strengthened, through repeated experience, they get stronger, forming habits of emotional reaction and response. We’re a bit like English law, which is based on precedent; when such and such occurs, we check back to see what the judges in previous cases did, and act in accordance with that.
For the most part we’re pretty dull creatures of habit. About 95% of the thoughts we have today, are exactly those we had yesterday, according to Deepak Chopra. And our reactions are most likely just the same. We are slaves to our conditioning, repeating old emotions to similar stimuli.
Physiology of the brain
The physical structure of the brain is in 3 parts, reflecting our evolution as a species:
- The brain stem / limbic system – gives rise to fast reactions eg fight or flight – a reptilian type of brain
- The sub-cortex –a mammalian type of brain which includes memory
- The cortex, which houses conceptualising capabilities and is uniquely developed in humans; this divides into two hemispheres, left for mathematical/language activity, and the right for visual/spatial activity.
The challenge for the brain, is to maintain equilibrium, between signals in its different parts. For example, the pre-frontal cortex may say stop doing xyz, while the limbic system creates arousal to act. Regulation of any system happens automatically, sending us signals eg ‘I’m hot, do something’, so then we act i.e. take off a jumper. These feelings, which swell up unbidden, create all kinds of cravings – ‘I want, or I don’t want’.
Because the world around us is always changing, we’re always getting these messages. Our brain keeps reacting, and we can get destabilised, distracted, and start creating an illusion or story as we try to make sense of what’s happening. A lot of the time we’re reacting to things that have already happened and past, so we miss what’s happening right now.
For example, we’re having a nice walk in the woods when we see something that is long, brown and curvy. The hippocampus (part of the limbic system which holds long term memory) quickly checks its known danger list and figures it might be a snake, so it sends a signal to the amygdala (which processes emotions) which sounds an alarm bell, so we jump away. Meanwhile the prefrontal cortex (which does logical thinking and can suppress emotions) gets into gear, and recognises that it’s also static and woody and in fact a stick; so we walk past it. We reacted appropriately to neutral, then unpleasant, then pleasant brain experiences, and all below our conscious level.
All this is chemically controlled. There are three main types of neurochemicals:
- Neurotransmitters, like glutamate which excites neurons to fire
- Neuromodulators, like serotonin which regulates mood, or dopamine which signals reward or approach behaviour
- Neuropeptides, like oxytocin which promotes loving behaviours
- Others like cortisol, which is released by the adrenal glands at times of stress (or perceived stress), stimulates the amygdala and suppresses the hippocampus
We are a sea of chemicals. For example, dopamine pushes us to seek out the things that our brain has learned are nice. When the reward is not felt as expected, dopamine falls, and we feel unsatisfied, and left with a craving that we can’t pinpoint.
Similarly if we’ve learned that something gives us a good feeling (eg an oxytocin surge), the neural circuits that recognise that opportunity get stronger, and we become more likely to notice that object next time. We get selective; ignoring or just not ‘seeing’ things that we’ve learned not to bother to see.
 Laboratory for Affective Neuroscience in Wisconsin
 Rick Hanson and Richard Mendius, ‘Buddha’s Brain’, 2009