During an experiment that tested space acuity, researchers found out that young adults who carry the APOE4 gene are prone to early onsets of Alzheimer.
A new study, conducted in Bonn, Germany, at the German Center for Neurodegenerative Diseases, shows that young adults are prone to develop Alzheimer. Nikolai Axmacher, senior researcher of the project, said that the results, although unclear, needs to be investigated in further studies in order to draw a conclusion.
About 75 young adults took part in this new study and about half of them carry the genetic material that triggers the onset of Alzheimer. The paper was published on October the 23rd in Science magazine. During this clinical study, researchers wanted to measure and observe how the brain handles concepts of spatial navigation.
According to Alzheimer’s symptomatology, the first area affected after the disease is triggered is the entorhinal cortex, which contains the grid-cells. These grid cells are highly specialized neurons, which can be found in many species. Grid cells allows us to ascertain and determine our position in space.
Although not all study subjects carried the genetic material that can cause early-stage Alzheimer, some of them did. Scientists estimate that one in six people carries the APOE4 gene, a protein that they believe to boost the risk of developing Alzheimer. Results prove indeed that, if they are carriers, young adults are prone to develop Alzheimer.
The APOE protein is crucial in the transportation of lipoproteins, fat-soluble vitamins and cholesterol. This protein is synthesized mainly by the liver. Evidence suggests that this protein can be found in other types of tissue such as brain, kidney and liver.
Further studies suggest that people who carry this gene are three times more predisposed to Alzheimer than people who don’t have the gene. Why are the grid-cells so important? As pointed out by the paper, the grid cells are the first brain structures to be affected by Alzheimer.
During this experiment, all participants were put in a virtual maze and given different tasks. By using a modified MRI scanner, researchers could see what goes on in the entorhinal cortex. The tasks were meant to test the participant’s spatial acuity. For example, some of them had to memorize a series of objects and their places in space and put them back together in the same positions. Others just had to navigate a virtual arena.
Scientists discovered that if the grid cells in the entorhinal cortex are affected, the brain tries to compensate using adjacent areas, mainly the hippocampus. Axmacher said that the less intact the grid cells are, the more the brain fires up the hippocampus.
Also those who carry the APOE4 gene, tend to have a different navigation strategy. Some of them try to find what we can call a vantage point in order to safely navigate through the maze, while others choose to start from the middle of the arena.
Although more research is required in order to produce viable results, researchers pointed out that this is a good starting point in detecting the early onset of Alzheimer.
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