Table 1

Morphologic parameters values of human complete (group A) apical and basal spines from the 40- and 85-year-old individuals

	Age		Average ± STD	Median	Range
Head volume (μm³)	40	Apical	0.3526 ± 0.25	0.2846	0.0274–1.6268
	40	Basal	0.3426 ± 0.22	0.2978	0.0324–2.206
	85	Apical	0.3816 ± 0.23	0.3331	0.0378–1.3154
	85	Basal	0.4103 ± 0.25	0.3559	0.0189–1.538
Neck length (μm)	40	Apical	0.6739 ± 0.4	0.5664	0.1839–3.1336
	40	Basal	0.7464 ± 0.46	0.6074	0.0353–2.9899
	85	Apical	0.8025 ± 0.56	0.5976	0.1865–3.7792
	85	Basal	0.7483 ± 0.47	0.5911	0.0818–4.0137
Neck diameter (nm)	40	Apical	339.9 ± 114.36	328.7	97.4–836.4
	40	Basal	361.67 ± 122	346.32	113.5–868.4
	85	Apical	340.08 ± 120	320.98	99.7–732.6
	85	Basal	356.66 ± 124	340.62	100.9–811.8

Since neck diameters below the resolution limit (∼200 nm) cannot be visualized using LM, these values correspond to those spines that were completely visualized (60%). Extended Data Table 1-1 shows the morphologic parameters values for the complete and repaired spines (groups A, C, and D).