Fig. 6: Tau nanoscale organization is regulated by synaptic activity.

a (i) Representative epifluorescence image of a WT hippocampal neuronal segment expressing VAMP2-pHluorin and Tau-mEos2, used for imaging under resting conditions (Low K⁺) and after stimulation (High K⁺). (ii) The inset of the presynaptic compartment in resting condition is shown at a higher magnification. (iii) Trajectory map of Tau-mEos2 in the unstimulated presynaptic compartment. (iv) The inset of the presynaptic compartment during stimulation is shown at a higher magnification. (v) Trajectory map of Tau-mEos2 in the stimulated presynaptic compartment. b Plot showing the total number of Tau-mEos2 trajectories within the presynapse, in resting conditions (black) and after stimulation (red). c Plot showing the total number of Tau-mEos2 trajectories within the axon, in resting conditions (black) and after stimulation (red). d–g Average MSD of total Tau-mEos2 trajectories and the corresponding area under the curve (AUC) in resting conditions (black) and after stimulation (red), in the presynapse (d, e) and in the axonal compartment (f, g). h Trajectory map of (i) recycling SVs and (ii) Tau-mEos2 in the unstimulated presynaptic compartment, obtained by dual-color single-tracking super-resolution imaging. (iii) Merged image. i Trajectory map of (i) recycling SVs and (ii) Tau-mEos2 in the stimulated presynaptic compartment, obtained by dual-color single-tracking super-resolution imaging. (iii) Merged image. j, k Representative Tau-mEos2 trajectories generated using segNASTIC showing instantaneous diffusion coefficients (the color bar represents log₁₀[μm²s^-1]) in a presynaptic region, determined by VAMP2-pHluorin intensity (inset), of a neuron that was unstimulated (j) and subsequently stimulated (k). l Percentage of Tau-mEos2 trajectories that are clustered. m Average cluster density of Tau-mEos2. n Average MSD of clustered Tau-mEos2 trajectories represented as the area under the curves (AUC). o Average apparent lifetime of Tau-mEos2 clusters. Data are displayed as mean ± SEM. Values were obtained from n = 29 synapses in (b, e), n = 23 axons in (c, g), and n = 15 synapses in (l, m, n, o). Data was obtained from ≥2 independent neuronal cultures. Statistical comparisons were performed using the two-tailed Student’s paired t-test. Source data are provided as a Source Data file.