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Fig. 8 | Biology Direct

Fig. 8

From: Onset, timing, and exposure therapy of stress disorders: mechanistic insight from a mathematical model of oscillating neuroendocrine dynamics

Fig. 8

Stress-induced transitions into an oscillating low-cortisol diseased state. An excitatory external stress I ext=0.2 is applied for 30 hrs. Here, the system reaches the new stable point set by I=1.2 before stress is terminated and the q-nullcline reverts to its original position set by I=1. a At intermediate values of 2.50<k<2.54, when two stable state arise, a transition from the normal high-cortisol state into the diseased low-cortisol state can be induced by chronic external stress. b Numerical solutions of cortisol level o(T) plotted against the original time variable T shows the transition to the low-cortisol diseased state shortly after cessation of stress. c and d If k>k R=2.54, only the normal stable state exists. The system will recover and return to its original normal state after a transient period of low cortisol

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