Fig. 2: Structural and functional dynamics of dendritic spines during the critical period.

a Average intensity projection of GCaMP6s fluorescence from a dendritic segment imaged every 5 days during the critical period (D1, D5, D10). Lost dendritic spines are labeled with an orange arrow, and added dendritic spines are labeled with a pink arrow. Scale bar = 5 µm. b Fraction of spines per neuron that were lost, added, or retained from D1 to D5 (dark bars) and from D5 to D10 (light bars). N = 16 neurons (928 total spines) tracked from D1 to D5, and 20 neurons (1144 total spines) from D5 to D10. Lines connecting points indicate neurons imaged across 3 timepoints (14 neurons). c Fate of spines (retained, added, or lost) from D1 to D10. N = 793 spines from 14 neurons. d Fraction of spines by cell that were retained from D1 to D5 (top) and from D5 to D10 (bottom) based on their response type on D1 or D5, respectively. Points represent the proportion for individual somata (Kruskal-Wallis test and post hoc Dunn’s test for response type). N = 16 neurons (D1 to D5) and 20 neurons (D5 to D10). e (left) Fates of 157 retained dendritic spines chronically imaged from D1 to D10, based on their responsiveness during binoc viewing. (right). Somatic responsiveness of the 14 neurons imaged from D1 to D10. f Same as (e) but for responsiveness during contra (c) or ipsi (I) eye viewing. Spines and neurons unresponsive to the contra and ipsi eye viewing are denoted as U. g Proportion of spines responsive in the same viewing condition (binocular (top), contra (middle), ipsi (bottom)) and timepoint (D1, D5, D10) as their soma. Points represent the proportion for individual somata (Kruskal-Wallis test). Binoc responsive neurons: N = 22 (D1), 13 (D5), and 9 (D10). Contra responsive neurons: N = 19 (D1), 12 (D5), and 7 (D10). Ipsi responsive neurons: N = 10 (D1), 2 (D5), and 4 (D10). For (d, g): error bars denote the mean ± SEM. n.s. = not significant. Source data are provided as a Source Data file.