PERSONALISED · Individual brain lateralisation, simulation of lesions, and stroke recovery – How the two halves of the brain interact: New insights from neuroimaging

Individual brain lateralisation, simulation of lesions, and stroke recovery – How the two halves of the brain interact: New insights from neuroimaging

Neurosciences have long been working under the assumption that each half of the brain (hemisphere) is dominant for a different set of functions. For example, language is considered a left hemisphere function while visuospatial functions are attributed to the right hemisphere. However, clinical data has repeatedly challenged our assumptions on brain lateralisation and a fundamental challenge in neuroscience is to reconcile neuroimaging findings with clinical evidence. PERSONALISED tackled these questions by measuring the dynamic interaction between the hemispheres. Using a large dataset of healthy volunteers (Human Connectome Project), the lateralisation was unravelled using the functional activation in each hemisphere during movie watching. This analysis allows us to identify when the brain responds to motion (e.g. an actor running), language (e.g. conversation), or auditory stimulation (e.g. bird chirping). Measuring these activations throughout the movies and for every part of the brain, we were able to measure where and when the brain responds to each type of movie snippet. We were able to demonstrate that overall, the brain is not functionally lateralised but dynamically adapts and shifts activation depending on the input. As such, PERSONALISED has led to theoretical and anatomical innovations that will be of interest to neurosciences and the clinical arena. The results of this project will enable us to build novel models of dynamic lateralisation in the largest population investigated thus far. In the future, validation in a stroke population would identify the impact of brain dynamics on the recovery of language and potentially offer novel treatment avenues. Further, neuroimaging methods are often ignoring anatomical and functional individual differences in the brain as they often rely on average templates. With the results from PERSONALISED, interindividual differences can be further studied in a dynamic functional framework to stratify different phenotypes. Overall, after one year into the project, we have mapped a comprehensive model of brain lateralisation across functions (e.g. language, visuospatial, motor) and its dynamic course across time. These findings advance our fundamental understanding of how the brain functions but also has far-reaching clinical implications (e.g recovery from a stroke). Beyond stroke, the output of this project can be extended to other datasets, diseases or clinical questions.

Data: CORDIS, © European Union