You are a unique individual and there will never be another you. Even if we could generate your clone with identical DNA (or, if you have an identical twin), you would still be unique. The physical, chemical, and mental environment that you experience from conception through your entire life adds a whole new layer of uniqueness.
But what about your brain? How do your unique memories and experiences shape your brain? It’s the connections between neurons that encode this information. This pattern of connections is known as your “connectome,” and by comparison your genome is small and simple. Your brain consists of tens of billions of neurons connected together by up to a quadrillion (1015) synapses.
We use a special type of magnetic resonance imaging (MRI) called diffusion MRI to map out the major connections within the brain. These are the white matter tracts that form the broad highways connecting regions of the brain together (we’re a very long way from looking at the streets in the cities themselves). Diffusion MRI is the only technique that allows us to look at these connections safely and non-invasively. Before this technique was developed in the 1990s, the only ways to determine connectivity were by injecting a tracer (dye) directly into an animal’s brain to see where it went, or by painstaking tracking from slice to slice in post-mortem brain sections.
While diffusion MRI is unlikely to reveal directly the subtleties of your personality anytime soon, research has already shown how the brain can rewire itself as it learns. An early study showed that learning to juggle changes the wiring of the brain. Mental challenges also change the brain, with studies showing changes related to learning a new language, playing a video game, or cramming for an exam. In a more extreme example, I was part of a group that studied a remarkable patient who spontaneously emerged from 19 years in a minimally-conscious state following a motor vehicle accident. Over a period of 18 months we could see changes in the connections in his brain which correlated with his recovery.
At the UVM MRI Center for Biomedical Imaging we use these and other techniques in several research projects, such as understanding the effects of chronic pain and cognitive treatment; sports-related head injuries; early diagnosis of Alzheimer’s disease; the lingering effects of premature birth in teenagers in a unique long-term study of 200 children in New Zealand.
Take a look at these sample brain scans:
Richard Watts, PhD, is a research associate professor in Radiology at The University of Vermont Medical Center. His career has been a seemingly random walk around the globe, including positions in York and Sheffield (UK), Grenoble (France), New York NY, Christchurch (New Zealand) and finally Vermont.