The neuroscience of hypnotherapy: Rewiring the brain for change

If the only thing you know about hypnosis is how performers use it on stage, you may think of it as control, with the belief the hypnotherapist takes over the mind. Hypnosis is a state of consciousness characterised by focused attention, absorption in imaginative experiences, dissociation from the environment, and suggestibility to therapeutic suggestions.

Neuroscientific research, such as a 2017 study published in Cerebral Cortex, shows subtle but significant changes in the brain of highly hypnotisable individuals, including enhanced connectivity in areas responsible for emotional regulation, self-awareness, and goal-oriented behaviour, alongside reduced activity in regions linked to cognitive control and anxiety. While susceptibility to hypnosis varies, the therapeutic process enables relaxation, introspection, and improved emotional regulation, offering a valuable tool for self-awareness and healing.

Understanding neuroplasticity

We metaphorically speak of the brain as malleable, like play dough. You can mould it and change it as you wish. It’s not quite as simple as this, but the scientific term is neuroplasticity, so it’s not so far from the truth. But what does this mean? For the brain is not really changing shape.

What we know is, when new memories form, preexisting synapses strengthen. Strengthening in this context means the neurons are more tightly connected. One neuron more readily triggers an action in the other. Robert Sapolsky says: “Strengthening means that the wave of excitation in a dendritic spine spreads farther, getting closer to the distant axon hillock” and “Extensive research shows that experience that causes repeated firing across a synapse strengthens it”.

Glutamate is the key neurotransmitter in this process. Dendritic spines contain one receptor, unless they respond to glutamate, in which case they contain two. One receptor is a non-NMDA receptor. For every small amount of glutamate that binds to the receptor, a small amount of sodium flows in, which causes a small burst of activity. The second receptor is usually unresponsive to glutamate. However, when a long train of glutamate stimulates the first receptor over and over, enough sodium flows in to activate it. Suddenly, it responds to all the glutamate and opens its channels, leading to a burst of excitation. This is learning, when someone says something once it goes in one ear and out the other. A few more times, and your brain starts to understand it. A few more times, a shed load of glutamate and sodium, and it's there, fully understood.

But how do you get it to stay? The process for this is long-term potentiation – LTP and explains long-term memory. When the second receptor finally activates, calcium flows in. This causes more copies of glutamate receptors to move into the dendritic spine’s membrane, making the neuron more responsive to glutamate thereafter. Additionally, it alters glutamate receptors already on the front line, making them more sensitive to glutamate signals. The calcium also causes more glutamate to release after future actions. In summary, there is more glutamate released, and the neurons listen better.

This learning happens throughout the brain and nervous system – it is the way we learn phone numbers and learn to fear certain things. It is also how chronic pain sufferers learn how to always feel pain.  It’s how addicts learn to associate things, such as location, with cravings.

There is something called long-term depression, which is the opposite of LTP. We stop learning and forget how to use the knowledge we have. Interestingly, transient stress (the good short-term stress that motivates us and keeps us ‘doing life’) supports LTP, contrasting to chronic stress which supports LTD.

It is important to note that this process is affected by many things, including the female menstrual cycle. The neurons can also remap in surprising ways. For example, musicians have a bigger area in their brain for hearing and processing musical sounds compared to people who don’t play music, and the younger the person becomes a musician, the stronger the remapping. Even more interesting is that remapping happens for people doing a thing and for people imagining they are doing a thing.

How does hypnosis support neuroplasticity?

During hypnosis, the brain experiences several changes that help improve focus and relaxation. It becomes better connected in certain areas, like the default mode network, which helps deepen concentration on internal thoughts and feelings. At the same time, areas involved in judgment and critical thinking, such as the prefrontal cortex, are less active, making it easier to accept suggestions and new ideas. Sensory areas of the brain become more responsive, increasing emotions or physical sensations.

During hypnosis, the brain is in the perfect state to form new connections, making it easier to learn new behaviours or change old ones. The brainwave activity shifts to slower waves, like theta and gamma, which link to relaxation and focused attention. When you are in the state of hypnosis, the brain is ready and open to listen, plus you have less awareness of external stuff, leaving more space for you. The ‘relaxation’ you feel is your body moving out of any chronic stress. Your brain is perfectly prepared for the process of neuroplasticity, helping you make beneficial long-term changes. Of course, these long-term changes don’t have to happen by actually doing a thing because you can make long-term changes by imagining doing a thing too.