IC‐P3‐174: Plasma Aβ level can be used as marker for AD treatment in PS1/APP Alzheimer's mouse model

(23.5 2.9 yrs.) were recruited and dichotomized into groups based upon e4 allele carrier status. During functional magnetic resonance imaging (fMRI), participants performed a simple object identification and categorization task and 24-hours later were given a surprise recognition test to evaluate their incidental encoding and recollection of the previously presented stimuli. Sustained (block) and phasic (event-related) fMRI signal characteristics associated with simple object categorization and successful incidental episodic memory encoding (i.e., subsequent recognition memory hits vs. misses) were evaluated using a hybrid model methodology. Structural differences in MTL grey matter were interrogated using voxel-based morphometry (VBM). Results: Despite the lack of differences in fMRI categorization task or subsequent memory performances, group-wise comparisons of the fMRI data revealed significant differences in both transient and sustained neural activity within the MTL as a function off APOE e4 allele carrier status. Both groups exhibited successful encoding-related activity in the MTL, though compared to non-carriers, e4 carriers exhibited significantly greater activity in bilateral hippocampus and parahippocampal gyri. Non-carriers exhibited greater sustained MTL activity (right anterior parahippocampal cortex) compared to e4 carriers. Grey matter tissue density differences were observed in bilateral rhinal and right parahippocampus, but these regions did not share spatial overlap with the significant fMRI loci.