Fig. 1

Experimental protocol, representative EEG and EMG traces, and validation of the position of implanted cannulas and of Aβ spreading. A Schematic representation of the position of cannulas (in CA1) and electrodes (surface of the cerebral cortex) and timeline of the experimental protocol. Ten-min infusions of 2-µL Aβscr or Aβo were performed every morning for 6 days. The EEG signal was recorded at baseline (BL) 24 h before beginning the injections, on days 2 (D2) and 5 (D5) of the injections, and 24 h following the last injection (INJ). B Representative EEG and EMG traces of the frontal-central bipolar signal obtained for wakefulness, SWS, and PS during the INJ day in one rat submitted to Aβscr injections and one to Aβo injections. C Approximate position of the cannulas in the hippocampus was determined using Nissl staining and marked with black dots for Aβscr (n = 11) and Aβo (n = 9) animals. Scale bars = 300 μm. D IHC images (magnification × 2.5) of Aβ staining (clone 6E10; red) in the hippocampus shown with DAPI staining (blue) in four rats submitted to 6 days of Aβscr (left) or Aβo (right) injections but not to EEG/EMG instrumentation. The position of the cannula tip is also observable for each rat