Learning difficulties linked to poor connectivity between brain regions

Written by Julia Titova (Future Science Group)

Scientists from the University of Cambridge (UK) have identified that poor connectivity between brain ‘hubs’, not issues with specific brain areas, may be associated with learning difficulties.

The findings, published in Current Biology, may explain why many drugs have not been proven effective for treating learning difficulties such as ADHD and implies that interventions should be less reliant on diagnostic labels.

Researchers have been pondering how exactly the brain develops learning difficulties for decades, but the wide range of different learning difficulties and inconsistency across diagnostic groups has made this field of research particularly challenging. In particular, researchers have struggled to identify specific areas of the brain that might give rise to learning difficulties and this has been further hindered by the vastly differing diagnoses between individuals.

Within this study, brain differences across a group of 337 children with learning difficulties and 142 children without learning-related cognitive problems were collected. A machine-learning algorithm was used to collate cognitive, learning and behavioral data as well as MRI scans, comparing the two groups. It was found that there were no brain regions that predicted having a particular learning difficulty. For example, there was no deficit in a certain part of the brain that corresponded to memory or language-related problems.

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The team discovered that children’s brains were organized around hubs and children with well-connected regions of the brain were much more likely to not exhibit learning difficulties. Children with poorer brain connectivity displayed severe cognitive problems. Duncan Astle, senior author of the study, explained that: “The severity of learning difficulties was strongly associated with the connectedness of these hubs, we think because these hubs play a key role in sharing information between brain areas.”

This discovery may explain why it has been so challenging to find effective treatment methods for learning difficulties. Most drugs target specific types of nerve cells but are ineffective at treating the ‘hub-based’ organizational structure that has been proposed.

It is anticipated that this research will pave the way for drugs that are more targeted to treat the connections between brain regions, enabling a real difference in the lives of children with learning difficulties.

Sources: Siugzdaite R, Bathelt J, Holmes J, Astle DE. Transdiagnostic brain mapping in developmental disorders. Curr. Biol. doi:10.1016/j.cub.2020.01.078 (2020) (Epub ahead of print); www.eurekalert.org/emb_releases/2020-02/uoc-ldd022420.php