The idea that the brain actually changes in response to what we do, what we think, and what we experience is fascinating. These responsive changes are called ‘neuroplasticity’, but what does it really mean? Can we make our brains bigger and better just by thinking? Thanks to modern brain scanning techniques, we have learnt much in recent years.
There are two imaging techniques commonly used to investigate changes to the brain’s structure: Magnetic Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI). Each type of scan looks at the brain in slightly different ways. MRI is used mainly to look at changes in grey matter whereas DTI visualises white matter. The grey matter covers the surface of the brain while white matter makes up the core (see image 1). Under a microscope, the white matter is made up of long wire-like nerve cell processes (called axons) covered in an insulating material called myelin. These transmit information between brain areas. The grey matter are areas tightly packed with the nerve cell (neuron) bodies, which contain the nucleus and DNA of each cell. Most of the changes in brain structure are due to changes in the numbers of connections between neurons (called synapses); there is, however, some evidence that humans can actually grow new neurons in adulthood.
Using these scanning techniques, researchers from the universities of Regensburg and Oxford studied the brains of volunteers that were learning to juggle. After just six weeks, they made an incredible discovery: volunteers who had learned to juggle showed a 5% increase in the white matter in an area of the brain associated with grasping objects in our peripheral vision (called the intraparietal sulcus). When the volunteers stopped juggling, this change disappeared, indicating that the increased volume is a direct effect of the training.
Physical exercise in general is a good way to boost your brain, and many studies using MRI have shown that older adults who exercise tend to have larger brain tissue volumes in certain areas. Surprisingly, these areas are nothing to do with control of the motoric skills we train while exercising; rather, they deal with cognition and memory, showing that brawn and brain are more closely linked than you may think.
These new scanning techniques are so sensitive that they can even give you hints about what job a person does. For example, studies of professional musicians showed differences in the size and structure of areas of their brains that control the complex motoric skills needed to play an instrument.
But what about emotional or cognitive experiences? Scanning people who frequently meditate using both MRI and DTI techniques reveals a number of structural brain changes in areas related to memory, and in regions that control attention and emotional regulation.
Of course, neuroplasticity can also lead to decreased brain tissue volume. Research of patients with post-traumatic stress disorder show that these patients have reduced volumes in areas controlling fear processing and memory. Children growing up in poverty also tend to have less tissue in brain areas dealing with language, reading, thinking and spatial skills.
So in other words, our brains are like our muscles; give it a good workout, and you can feel (and now see!) the changes!
By Magdalena Kegel
Draganski, B. et al. Changes in grey matter induced by training Newly honed juggling skills show up as a transient feature on a brain-imaging scan. Nature 427, 311–312 (2004).
Erickson, K. I., Leckie, R. L. & Weinstein, A. M. Physical activity, fitness, and gray matter volume. Neurobiol. Aging 35, S20–S28 (2014).
Ho, N. F., Hooker, J. M., Sahay, a, Holt, D. J. & Roffman, J. L. In vivo imaging of adult human hippocampal neurogenesis: progress, pitfalls and promise. Mol. Psychiatry 18, 404–16 (2013).
Kang, D. H. et al. The effect of meditation on brain structure: Cortical thickness mapping and diffusion tensor imaging. Soc. Cogn. Affect. Neurosci. 8, 27–33 (2013).
Münte, T. F., Altenmüller, E. & Jäncke, L. The musician’s brain as a model of neuroplasticity. Nat. Rev. Neurosci. 3, 473–478 (2002).
Noble, K. G. et al. Family income, parental education and brain structure in children and adolescents. Nat. Neurosci. (2015).
O’Doherty, D. C. M., Chitty, K. M., Saddiqui, S., Bennett, M. R. & Lagopoulos, J. A systematic review and meta-analysis of magnetic resonance imaging measurement of structural volumes in posttraumatic stress disorder. Psychiatry Res. Neuroimaging 1–33 (2015).
Scholz, J., Klein, M. C., Behrens, T. E. J. & Johansen-Berg, H. Training induces changes in white-matter architecture. Nat. Neurosci. 12, 1370–1371 (2009).