Fig. 2

Synaptic pathology in the somatosensory cortex layer 5 following PFF injection. A Representative images of NeuN-stained neurons in the somatosensory cortex 20 weeks post injection (p.i.). Scale bar = 100 µm. B Quantification of neuronal density in the somatosensory cortex. C Localization of pS129-α-syn aggregates in layer 5. Scale bar = 100 µm. D Traces showing sEPSC recordings from neurons in the same layer. E Frequency of sEPSC events (PBS = 3.06 ± 0.53 Hz; PFF = 1.26 ± 0.17 Hz). F Amplitudes of sEPSC events (PBS = 17.29 ± 0.99 pA; PFF = 16.19 ± 0.61 pA). G Cumulative probability of sEPSC interevent interval. H Cumulative probability of sEPSC amplitude. I Images of synapses in layer 5, identified by immunodetection of the presynaptic marker VGLUT1 and postsynaptic marker PSD95. Scale bar = 20 µm. J Quantification of VGLUT1 intensity. K Quantification of PSD95 puncta/µm². L Quantification of synapse density (synapses/µm²) by co-localization of VGLUT1 and PSD95. M Golgi staining of apical dendritic spines from layer 5 pyramidal neurons. Scale bar = 5 µm. N number of spines per micron. O–S Ratio of spines: thin (O), stub (P), mushroom (Q), long thin (R), and filopodia (S). Data are expressed as means ± S.E.M. (A–C, n = 5 and 4 mice for PBS and PFF, respectively; D–H, n = 13 and 20 neurons for PBS and PFF, respectively, from 4–5 mice; I–L, n = 4 and 6 mice for PBS and PFF, respectively; M–S (PBS, n = 31 and 34 neurons for PBS and PFF, respectively, from 5 mice; *p < 0.05, **p < 0.01, ***p < 0.001; Student’s t-test)