This is a study in young, neuropsychological healthy participants who carry a risk gene for Alzheimer's disease in order to detect possible early changes in brain activity in a working memory task.
A large number of studies with functional magnetic resonance imaging (fMRI) have shown that young and neuropsychological healthy ApoE4 carriers have altered brain activity. This has also been shown for working memory tasks, interestingly in the absence of differences in behavior (e.g. accuracy and response time). Recent models of the neuronal principles of working memory propose that regions of the medial temporal lobe (MTL), in particular perirhinal cortex (PrC), entorhinal cortex (EC), and the CA1 subregion of the hippocampus are required for the maintenance of stimulus-specific patterns in working memory tasks. In turn, the entorhinal cortex, especially lateral entorhinal cortex, is one of the regions earliest affected by typical Alzheimer's pathologies.
We investigate whether a disturbed maintenance of stimulus-specific patterns in working memory tasks in the entorhinal cortex and hippocampus can already be observed in young, neuropsychological healthy carriers of the ApoE4 allele.
First, carriers of the risk gene and the same number of control subjects who do not carry the risk gene are identified from a larger group of young subjects (e.g. students) using a saliva sample.
After checking the exclusion criteria (e.g. non-removable metal objects, fear of confined spaces etc.), the actual examination takes place in a 60-minute session. This includes MRI imaging, during which a classical working memory task with images of everyday objects is performed in which objects are shown and, after a maintenance phase with a black screen, further objects are shown. The participants must now decide whether the objects shown are identical or only similar to the objects previously shown. This task takes about 35 minutes, followed by 15 minutes of high-resolution structural imaging of the brain.
Principle investigator: Prof. Dr. Nikolai Axmacher
Start of the study: 2018
Status: mono centric (DZNE Bonn), ongoing, recruiting active