Figure 3. ApoE4 further reduces spine density in the cortex at 1 year. A, Averaged total spine density (56 neurons/group). B, Averaged AO spine density (28 neurons/group). C, Averaged BS spine density (28 neurons/group). *p < 0.05 compared with APOE3. D, Cumulative distribution of spine length. E–G, Mouse brains were Golgi stained and cortical layers II/III imaged at 1 year of age (n = 4 mice/genotype). E, Averaged data include total spine density (56 neurons/genotype). F, Averaged data include AO spine density (28 neurons/genotype). G, Averaged data include BS spine density (28 neurons/genotype). *p < 0.05 compared with APOE3. H, Cumulative percentage distribution of spine length. APOE4 TR mice had a significant shift in distribution toward smaller spines compared with the other APOE TR (E3, E2) mice at 1 year of age. I, J, Mouse brains were Golgi stained and granule cells in the dentate gyrus were imaged at 3 months (n = 4). I, Averaged total spine density for all genotypes (28 neurons/group). J, Cumulative percentage distribution of spine length. K, L, Mouse brains were Golgi stained and granule cells in the dentate gyrus were imaged at 1 year (n = 4). K, Averaged total spine density (28 neurons/group). L, Cumulative percentage distribution for spine length. APOE2 TR had a significant shift in distribution toward shorter spines compared with APOE (E3, E4) TR mice.