Table 4. Correlation between miRNA expression and Alzheimer's-related changes (P values for linear regression test) for a selected subset of miRNAs.

MiRNA	miR-15/107 group	Enriched in GM or WM	Gray matter by neuropathology			White matter by neuropathology
			DPs	NPs	NFTs	DPs	NPs	NFTs
miR-124	N	GM	0.152	0.463	0.864	0.871	0.908	0.863
miR-125b	N	Neither	0.678	0.832	0.460	0.876	0.780	0.794
miR-103	Y	GM	0.014	0.082	0.399	0.214	0.344	0.627
miR-107	Y	GM	0.034	0.114	0.465	0.374	0.419	0.631
miR-15a	Y	WM	0.005	0.041	0.269	0.240	0.618	0.932
miR-15b	Y	WM	0.081	0.184	0.526	0.213	0.509	0.869
miR-16	Y	WM	0.036	0.045	0.227	0.112	0.296	0.476
miR-195	Y	WM	0.033	0.070	0.361	0.824	0.820	0.733
miR-424	Y	Neither	0.416	0.405	0.717	0.062	0.018	0.018
miR-128	N	GM	0.042	0.229	0.782	0.775	0.735	0.845
miR-29a	N	GM	0.031	0.075	0.441	0.915	0.808	0.934
miR-29b	N	GM	0.058	0.182	0.702	0.770	0.882	0.898
miR-29c	N	GM	0.033	0.130	0.551	0.566	0.897	0.636
miR-214	N	Neither	0.009	0.116	0.486	0.039	0.293	0.660

Testing specific miRNAs for correlation with the density of AD-type lesions. These miRNAs were chosen because they had been previously described to have altered expression in association with AD. Prior studies did not test white matter separately. Here, we used the P value for the linear regression to test for statistical significance (P < 0.05, bold values). Negative correlation between miRNA variability and AD pathology are in roman, positive correlation in italics. Note that most members of the miR-15/107 gene group (miR-15a, miR-15b, miR-16, miR-195, miR-424, miR-103, and miR-107) show a negative correlation to AD-type amyloid plaques, and only in gray matter, with the exception of miR-424, which shows a positive correlation to AD-type pathology that appears most specific to white matter samples. Complete gene expression data for the various miRNAs are provided in Supplemental Table 1