by Raphael Wurm
The session on neurodiversity in brain organisation brought to the stage something that we all know, but perhaps do not always think about: the brain is not symmetrical. While we are all aware of language lateralisation, researchers now believe that individuals differ much more from the overall population than previously thought. This variability, found in more than 90% of cortical and subcortical regions, enhances multitasking, energy efficiency, and action control in the energy-hungry brain system. So, while there is a good evolutionary explanation, the implications for disease have sometimes been overlooked!
The symposium began with a talk by Emma Karlsson from Ghent, Belgium, who spoke on individual variability in functional brain organisation. Karlsson’s exploration of this topic underscored how population-level asymmetries deviate in individuals to a greater extent than often assumed. Refining our understanding of this personal asymmetry map will open up doors to diagnostic but also therapeutic options in the future.
Next, Robin Gerrits, also from Ghent, Belgium, presented on the clinical considerations of natural variability in asymmetrical brain organisation. Gerrits discussed how therapeutic protocols, such as transcranial magnetic stimulation (TMS), often apply a lateralised approach and should, therefore, consider individual brain asymmetry in patients. He gave the striking example of depression, in which some patients show increased excitations precisely where we would stimulate, showing how this could in fact be detrimental.
Annakarina Mundorf from Hamburg, Germany, then addressed the role of laterality in neurological diseases. Her talk, and her extensive experience in this field, gave a great overview of almost all parts of neurology, showing that asymmetry is important in many more diseases than you might think. She highlighted disorders such as Parkinson’s disease and Alzheimer’s disease, where the clinical picture, of course, suggests an uneven distribution, but also showed how this concept extends to multiple sclerosis – and gave an explanation for why sensory symptoms often only affect one side of the body. Mundorf spanned the arch from animal studies back to the clinic, showing how these asymmetries could be used to personalise and improve treatment.
She was followed by her colleague Sebastian Ocklenburg, also from Hamburg, who concluded the session with a talk on amygdala asymmetries in clinical and non-clinical populations. As the amygdala is central to the processing of many higher cortical functions, it is not only important in disease, but can also be studied exquisitely in healthy cohorts. Ocklenburg explored the structural and functional differences between the right and left amygdala, noting their implication in neurodevelopmental, psychiatric, and neurological disorders. He underscored how understanding these asymmetries can enhance research design and further unravel disorder-specific implications, hopefully advancing treatment options.
In summary, this session underscored the importance of recognising and understanding the individual variability in brain organisation. While fascinating on its own, the clinical implications in an era of rapidly expanding structural and functional interventions cannot be overstated. If you want to know more about what study design and personalised medicine will need to take into account, check out all of the talks here.