A Wellcome Trust article highlights the work of Professor Heidi Johansen-Berg at the University of Oxford and her research exploring the structural changes in the brain’s white and grey matter that underlie learning. Understanding the precise cellular nature of those changes may improve diagnosis of brain damage and therapeutic interventions in stroke.
Modern neuroscience supports the notion that our brains are divided into discrete “compartments”, each in charge of a different function or set of functions.
Mapping those compartments more precisely – and understanding how the tissue structure in each region allows us to do specific things – is a fundamental challenge for neuroscience.
Thanks to advances in imaging techniques, we now know roughly which bit of the brain looks after what. Functional magnetic resonance imaging (fMRI) – which measures blood oxygen levels in tissue – has shown which regions are activated when we make a decision, take a risk, control our temper or play a game of tennis. But the brushstrokes are broad and the picture remains impressionistic. We haven’t yet found a safe, non-invasive way to penetrate the deep tissues of the living human brain – or to reveal its microscopic cellular structures (cytoarchitecture).
“Conventional brain scans or fMRI give fairly gross landmarks,” says Professor Johansen-Berg. “We can see activity in a certain part of the brain when people are performing a specific task. But we can’t tell where one area ends and another begins because it all just looks grey.”
Neither do we know which differences in tissue composition between disparate brain regions account for these different functions. What variations in the type, size, number and patterning of cells and other micro-structures in a particular brain region allow us to evaluate two choices as opposed to run for a bus, for example?