Researchers in the US have used brain imaging techniques to identify an area of the brain, called the lateral entorhinal cortex (LEC), that is particularly vulnerable in Alzheimer’s disease. The study is published on 22 December in the journal Nature Neuroscience.
The team from New York used high resolution functional magnetic resonance imaging (fMRI) to look at changes in metabolism in the brain in people with Alzheimer’s and mice bred to show signs of the disease. They studied an area of the brain called the entorhinal cortex, that has been implicated in the early stages of Alzheimer’s and can be split into two regions – the medial entorhinal cortex and the lateral entorhinal cortex. The entorhinal cortex is part of the brain’s memory network, linking up the hippocampus – where memories are processed – to other areas of the brain.
Using MRI brain scanning techniques the team visualised changes in the brains of 96 people without dementia, who were followed for 3.5 years. At follow-up, 12 had progressed to mild Alzheimer’s, meaning earlier features on their brain scans could be indicative of the first changes in the disease. The remaining participants remained free from dementia and their scans were used for comparison. The researchers found changes in the brain specifically in the lateral entorhinal cortex in those who went on to be diagnosed with Alzheimer’s, which correlated with performance on a particular type of memory test.
To understand more about the molecular changes in this area of the brain, the team used mice bred to have a build-up of two hallmark Alzheimer’s proteins within the entorhinal cortex. Brain imaging of the mice showed that those with a build-up of amyloid and tau showed changes in the lateral entorhinal cortex in comparison to mice expressing only amyloid or only tau. The findings suggest that both proteins drive the progression of the disease in this vulnerable area at a faster rate than either alone. The researchers also observed that the disease appeared to spread from the lateral entorhinal cortex to other areas of the brain.
Dr Laura Phipps of Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“Understanding why some areas of the brain appear more vulnerable to damage in Alzheimer’s could help to explain patterns of symptoms as well as highlight areas of the brain that need more detailed study. There is still a lot to understand about the molecular processes driving Alzheimer’s and how the amyloid and tau proteins cause damage in the brain. We must continue to invest in research to find these answers for the half a million people living with Alzheimer’s in the UK today.”