Fig. 4: Especially upper and middle spine head membrane areas respond to LTD induction by displaying transiently increased PIP2 signals.

The spine heads were further subdivided into lower, middle, and upper head according to the schematic (a). Quantitative analyses of the PIP₂ labeling densities in DIV14-16 neurons after NMDA treatment (see Fig. 3) in the upper (b), middle (c), and lower head (d). Quantitative analyses are based on the total spine data at 0 min (steady state) in each assay. For a comparison of absolute data for 0 and 3 + 7 min not normalized to the respective controls with corresponding data obtained from an independent, untrained experimenter see Supplementary Fig. 3. 0 min, n = 159; 1 min, n = 36; 2 min, n = 53; 3 min, n = 49; 5 (3 + 2) min, n = 50; 10 (3 + 7) min, n = 59; 15 (3 + 12) min, n = 44; 30 (3 + 27) min, n = 35 ROIs each (upper, middle, and lower head) from 3 to 16 independent assays with different incubation times. Data, mean ± SEM. Statistical significance calculations, Kruskal–Wallis/Dunn’s. *P < 0.05; **P < 0.01. P-values are reported directly in the figure. For numerical source data, see Supplementary Data 1.