Whilst the changes that occur in our brains during childhood, adolescence and old age have been well documented, it has been assumed that brain structure is relatively stable from early-adulthood through to mid-adulthood. However, research from China published in Frontiers In Neuroscience has found microstructural changes in the brain that are correlated with age.
Scientists analysed a series of brain scans from 111 participants aged 18-55 years. The brain scans employed a form of magnetic resonance imaging (MRI) known as diffusion tensor imaging (DTI) which show the brain's white matter fibres. The researchers were able to measure fractional anisotropy, which can be used as an index of nerve fibre density and axonal diameter, together with level of white matter myelination. Results indicated that there was a negative correlation between ageing and brain structures such as the bilateral genu of the corpus callosum, the corticospinal tract, the fornix and several other brain pathways. The correlations were that dramatic that scientists were able to accurately estimate the age of the participant simply on the basis of their brain scan. Decline of the above brain regions has been linked with some of the cognitive problems associated with old age, including decreased reaction times, reasoning and memory.
This study is interesting because it illustrates structural dynamism during a period of life in which neuroanatomy was thought to be relatively stable. The next step is to find out the extent of variability across individuals and how this change might be linked to disease and disorder.
You can read the entire paper here.