Posterior Memory System Connectivity In Older Adults With Subjective Memory Complaints
Abstract
Subjective memory complaints, perceived decline in memory functioning without objective cognitive deficit, could demarcate incipient dementia. However, characteristics of the brain in individuals with subjective memory complaints remain unclear. Here, I evaluated differences between healthy older adults aged 50 to 85 with (n = 35, Age = 68.51 ± 7.66, 22 female), and without (n = 48, Age = 66.96 ± 8.79, 29 female) subjective memory complaints in posterior hippocampal, retrosplenial, and medial prefrontal cortex functional connectivity. I also evaluated diffusion characteristics of the parahippocampal and cingulate gyrus cingulum fiber bundles. Participants with subjective memory complaints performed poorer than controls on a measure of visual working memory. However, there were no differences between groups in functional connectivity between posterior hippocampus and posterior cingulate cortex, or between posterior cingulate and medial prefrontal cortices. Furthermore, groups did not differ in cingulum neurite density. Functional coupling between memory components may be largely intact in subjective memory complaints.