Heart Rate and Heart Rate Variability Assessment Identifies Individual Differences in Fear Response Magnitudes to Earthquake, Free Fall, and Air Puff in Mice
(A) Instant HR responses of an individual mouse during three trials of earthquake stimuli, trial #1, trial #4 and trial #7. The red vertical dashed lines indicate the onset of the earthquake (0.5 s). (B) Poincaré plots of the same mouse’s R-R intervals of 30-s pre-stimulus (grey line) and 30-s post-stimulus (red line) period in trial #1, trial #4 and trial #7. Note the reduction of HRV in response to earthquake at trial #1, and such reduction effect became weaker at trial #4 and trial #7. (C) The average HR response to earthquake (1st trial). (D) The average CV of R-R intervals upon 1st trial of earthquake. (E) The average RMSSD of R-R intervals upon 1st trial of earthquake. The average curves of 30-s pre-stimulus period were plotted as grey lines, whereas the average curves of 90-s post-stimulus period were plotted as red lines. The shadows around the average curves indicate error bars (SEM); n = 7.