Figure 4.

Susceptible mice exhibit increased switching between NREM and wake bouts in NREM↔Wake

(A I-IV). Susceptible mice exhibit greater number of bouts of NREM and Wake in NREM↔Wake compared with resilient mice pre- and post-CSD in the light. Pre-CSD, in the dark, the number of bouts of all vigilance states was greater in susceptible compared to resilient mice (p < 0.05 for all comparisons).

(B) Pre-CSD: Model summarizing the findings of sleep wake dynamics associated with vulnerability to stress. A greater pull towards the wake state in the sleep wake flip flop switch might lead to early termination of the sleep bouts or shorter duration with no apparent change in the wake bouts duration in the light. The greater pull leads to increased switching between the sleep and wake states only in NREM↔Wake.

(C) Modeling of the sleep state(s) in NREM↔Wake as “short sleep” and in NREM→REM→Wake as “long sleep” and the use of 2-state discrete Markov model to assess the stability of “short sleep” state and the probability of transition from “short sleep” to “long sleep.” (CI) Susceptible mice exhibited greater stability of “short sleep” state and (CII) lower probability of transition to “long sleep” state relative to resilient mice pre-CSD only in the light. ∗ denotes, p < 0.05. One-way ANOVAs followed by post hoc Tukey tests were performed for multiple comparisons. N = 7-8 for each group.