Figure 4

Relationship between spine size and spine elimination. (A) The sizes (both length (a) and width (b)) of spines were measured as illustrated. The sum of the values "a" and "b" was calculated and utilized as an index of spine size. (B1) Spines eliminated within two or seven days were smaller than the spines maintained for the same period. Images are comparisons over two days. An arrow indicates an eliminated spine. The bar graph shows the combined data from images taken over two or seven days, as the frequency distribution of each population was indistinguishable. (B2) When spines were imaged with intervals of 28 days, the sizes of eliminated spines were similar to those of stable spines. An arrow indicates an eliminated spine. (C1) Spines eliminated within two or seven days were smaller than the stable spines also in the LPS-treated group. An arrow indicates an eliminated spine. (C2) Spines eliminated 28 days after LPS treatment had comparable sizes with those maintained. An arrow indicates an eliminated spine. Importantly, the average sizes of eliminated spines between control and LPS-treated groups were not different at two different time points (less than seven days in B1/C1, at 28 days in B2/C2), indicating that the effect of LPS is not selective for a specific size of spines. ***, p < 0.001. Scale bars, 2 μm.