Fig. 1

Power spectra and spectrograms of the 100 kHz ultrasound (US) and white noise (WN) delivered to experimental rats. (a and b) Power spectra of the WN (a) and 100 kHz US (b) sound source signals generated using Adobe Audition (Adobe Inc. USA). (c and d) The power spectra of WN (c) and 100 kHz US (d) recorded inside the soundproof box (green line). The red line represents the recorded sound inside the soundproof box with no-sound played (baseline). (e and f) The WN (e) and 100 kHz US (f) spectrogram in the experimental environment for immunohistochemical assay, HE evaluation, and EPM test. (g, h) The WN (g) and 100 kHz US (h) spectrogram in the conditioning session in tone fear conditioning test. (i and j) The WN (i) and 100 kHz US (j) spectrogram in the test session in tone fear conditioning test.