Fig. 1
AβO1–42 impairs in vivo-like, optogenetically induced theta-nested gamma oscillations in hippocampal slices. a Western blot of SDS-PAGE showing AβO1–42 (trimer, tetramer, and large oligomers) after incubation at 4 °C for 0 h (left) and 18 h (right). b Micro-injection of AAV-CaMKII-ChR2-mCherry into hippocampal CA1 area of C57BL/6 mice. c Fluorescence image of ChR2-expressing PCs (ChR2-PC). SO, stratum oriens; SP, stratum pyramidale; SR, stratum radiatum. d Experimental schematic showing sinusoidal (5 Hz) blue light (470 nm) stimulation of ChR2-PC and field recordings in the CA1 area of hippocampal slices in vitro. e–g Sinusoidal blue light stimulation induces theta-nested gamma oscillations as shown in the band-pass filtered LFP (top) and the corresponding spectrograms (bottom) in DMSO-treated slice (e), after 20-min treatment of either AβO1–42 (f), or AβO42–1 (g). h–j Mean power spectral density (PSD, shade indicates SEM) of gamma oscillations (h), mean peak power (i), and mean peak frequency (j) of gamma oscillations in DMSO-treated slice (black) and following 20 min of AβO1–42 treatment in the same slices (red) or in DMSO-treated slice (black) and following 20 min AβO42–1 treatment in the same slices (magenta). k, l Representative comodulograms showing phase-amplitude coupling of gamma oscillations to theta cycle (k) and mean modulation index (l) in each condition. Paired Student’s t test (i, j, l, ***p < 0.001, ns: not significant). Data are represented as mean ± SEM