Changes in Heart Rate Variability Are Associated with Expression of Short-Term and Long-Term Contextual and Cued Fear Memories
Figure 5
Changes in heart rate and heart rate variability in relationships with freezing behavior during contextual recall.
(A–B) The HR and CV of stage-I and stage-II freezing period in 1-hr contextual retention test. n = 11; *P<0.05, ***P<0.001, paired t test. (C) The freezing responses during contextual habituation, contextual 1-hr retention and contextual 1-day retention. n = 8; ***P<0.001, one-way repeated measures ANOVA and Tukey post hoc test. (D) The duration of stage-I during contextual habituation, 1-hr contextual retention and 1-day contextual retention. n = 8; ***P<0.001, one-way repeated measures ANOVA and Tukey post hoc test. (E–F) The CV of stage-I and stage-II during contextual habituation, 1-hr contextual retention and 1-day contextual retention. n = 8; *P<0.05, **P<0.01, one-way repeated measures ANOVA and Tukey post hoc test. (G) The averaged freezing responses in eleven mice were anti-correlated with the averaged CV of instant HR in 1-hr contextual retention (r = –0.851, P<0.001). (H) The averaged freezing responses in eight mice were also anti-correlated with the averaged CV of instant HR in 1-day contextual retention (r = –0.870, P<0.001). All data are plotted as mean ± s.e.m. (error bars).