Alzheimer's risk changes the sense of spatial orientation early on

Activation in the brain area changed for navigation at Alzheimer's risk
Genetically increased risk of Alzheimer's disease already shows early altered activation patterns in a brain region that is important for spatial navigation. Scientists from the Ruhr University Bochum have published a study in the journal "Science", according to which the so-called entorhinale cortex in young adults with genetically increased risk of Alzheimer's shows altered activation patterns. While non-risk-takers show a characteristic lattice pattern in the activity, this pattern is reduced in risk carriers, according to the announcement of the Ruhr University.

In addition to the loss of memory, Alzheimer's patients also show a disorientation which, according to the latest findings, is due to impairments of the brain region which are required for spatial orientation. In this area of ​​the brain, modified activation patterns can already be detected by functional magnetic resonance tomography at a very early stage of the disease, the scientists report. "Our study contributes significantly to a better understanding of early changes in Alzheimer's dementia," said Nikolai Axmacher of the RUB Institute for Cognitive Neuroscience.

The activation patterns in the brain are changed at an early stage if there is an increased risk of Alzheimer's. (Image: SSilver / fotolia.com)

Activation pattern changed long before the onset of a disease
In the brain area of ​​the entorhinal cortex are the so-called "grid cells". These cells fire when activated in a spatial grid pattern, explain the scientists of the Ruhr University Bochum. Studies have already shown in studies in 2010 that this special cell system in humans can be detected indirectly by means of functional magnetic resonance tomography while navigating through a virtual landscape. Nikolai Axmacher and colleagues used the method to study the "grid cell" system in the entorhinal cortex of young students with and without Alzheimer's risk genes. The "risk takers" showed a less stable grid pattern in the entorhinal cortex - and decades before they could possibly develop Alzheimer's dementia, "reports co-study author Lukas Kunz, who conducted the experiment at the German Center for Neurodegenerative Diseases in Bonn.

Modified navigation in virtual space
Also, the risk carriers had greater difficulties in virtual navigation and moved less frequently in the middle of the virtual landscape, which suggests a change in navigation strategy, according to the announcement of the Ruhr University. Overall, the effects on the activation patterns in the entorhinal cortex were very clear, so that they could possibly serve as an aid in the diagnosis in the future. "Now it has to be examined whether similar changes also occur in the elderly in the early stages of Alzheimer's dementia and whether they can be influenced by medication," emphasizes study leader Axmacher. (Fp)