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Marc Debnam
Several theories link processes of development and ageing in humans. In neuroscience, one model suggests that age-related brain degeneration in healthy humans mirrors development: in other words, the areas of the brain that are thought to develop later also degenerate earlier. So far, the MRI studies looking for such a link between healthy ageing and development in the grey matter have led to different, and sometimes contradictory, results.
In a paper published in Proceedings of the National Academy of Sciences on 24 November 2014, Gwenaëlle Douaud, with colleagues from the Oxford Centre for Functional MRI of the Brain and elsewhere, presents data-driven evidence that supports this model of mirroring development and ageing.
The team analysed brain structural variation using MRI scans across 484 healthy participants (between the ages of 8 and 85). They were able to see a particular network of brain regions which develops relatively late during adolescence and shows accelerated degeneration in old age compared with the rest of the brain.
This same network is also particularly vulnerable to unhealthy developmental and ageing processes, such as schizophrenia and Alzheimer’s disease. It is also associated with intellectual ability and episodic memory, whose impairment contributes to key symptoms of schizophrenia and Alzheimer’s disease.
These regions seem to be more vulnerable than the rest of the brain to both schizophrenia and Alzheimer's. - Gwenaëlle Douaud
The results suggests that the common spatial pattern of abnormalities observed in these two disorders, which emerge at opposite ends of the life spectrum, might be influenced by the timing of their pathological processes in disrupting healthy cerebral development and ageing.
This research therefore provides, for the first time, evidence of a fundamental link between development, ageing, and disease processes in the brain.