Ic‐p‐046: memory system functional connectivity and working memory performance in subjective memory complaints

Subjective memory complaints (SMC), perceived decline in memory function without objective deficit, associate with future decline. We compared memory performance, and functional connectivity (FC) of anterior and posterior memory systems, between healthy older adults with and without SMC. We also examined effects of SMC on uncinate and cingulum diffusion characteristics. Resting fMRI and cognitive data were available for 83 adults; 48 without (Age = 67.0 ± 8.8, 29 female) and 35 with SMC (Age = 68.5 ± 7.7, 22 female). Diffusion data were available for a subsample (N = 38; 27 controls, 11 SMC). fMRI preprocessing included ICA-AROMA (Pruim, et al., 2015). We defined regions of interest (ROIs) based on extant literature coordinates. The anterior system included hippocampal head, perirhinal/entorhinal, amygdala, lateral orbitofrontal, ventral temporopolar, and inferior anterior cingulate ROIs. The posterior system included hippocampal body, parahippocampal, inferior parietal, retrosplenial, precuneus, superior anterior cingulate, and posterior cingulate ROIs. Fisher Z transformed correlations of paired ROI mean time courses assessed FC. From diffusion images, we extracted average neurite density (Zhang, et al., 2012) from reconstructed cingulum and uncinate fiber tracts (Yendiki, et al., 2011). General linear models evaluated effects of SMC on average system FC, specific pairwise connections, and neurite density. Age, gender, and test-site were covariates. Furthermore, we examined the relationship between SMC and performance on the Wechsler Memory Scale IV (WMS-IV). We determined significance after Bonferroni correction for the number of models tested per research question. SMC Participants showed lower average posterior system FC (β = -.22, p = .02); and lower retrosplenial-precuneus FC specifically (β = -.35, p = .001, Figure 1). We observed no group differences in neurite density. SMC participants had poorer visual working memory (VWM) performance (β = .11, p = .01).