The two sides of the brain in popular psychology are often used to stand in for particular cognitive modes, with the ‘left-brain’ responsible for everything analytical, rational and linguistic and the ‘right-brain’ responsible for creativity and emotion. Although this is certainly an oversimplification, the brain does possess regions specialised for different functions, such as language processing and facial recognition, and these are undoubtedly distributed differently over its two sides. But how might these functions be reflected in the structure of the brain? Or, put conversely, how might brain structure enable these broader cognitive modes? Even with respect to language processing, one of the most typically ‘left-brained’ functions, this relationship remains unclear.
Moreover, our brains are massively interconnected. The corpus callosum is our major cerebral information highway, linking the two sides of the brain with more than 200 million nerve fibers. How might the asymmetry of the ‘left’ and ‘right’ brains relate to the means of communication between them? It is conceivable that as humans evolved, we needed to use our limited brain size efficiently by developing more and more specialised brain functions. We might expect that less communication was consequently needed between the sides of the brain, because local connections were favoured as more economical. In an alternative view, integrating across these widely spread-out specialised regions might require an information highway with even more ‘lanes’. These are two possibilities, but more research is required to illuminate the nature of the relationship between brain asymmetry and the brain’s major communication pathway.
It is important to establish what this relationship might look like in the general population, as brain asymmetry has been implicated in diverse conditions such as autism, obsessive compulsive disorder, schizophrenia and Alzheimer’s disease. Such a baseline could help researchers identify where the brain differences lie in these conditions, enhancing clinical understanding and informing possible treatment approaches.
This project will run for three years (36 months) and will seek to outline any links between brain asymmetry and the corpus callosum, how these might relate to broader cognitive functions and what factors might play a role in how they are expressed.
