  Behavioral control over stressful stimuli induces resilience to future
conditions when control is lacking. The medial prefrontal cortex(mPFC) is a
critically important brain region required for plasticity of stress resilience.
We found that control over stress induces plasticity of the intrinsic
voltage-gated conductances of pyramidal neurons in the PFC. To gain insight
into the underlying biophysical mechanisms of this plasticity we used the
conductance- based neural simulation software tool, NEURON, to model the
increase in membrane excitability associated with resilience to stress. A ball
and stick multicompartment conductance-based model was used to realistically
fit passive and active data traces from prototypical pyramidal neurons in
neurons in rats with control over tail shock stress and those lacking control.
The results indicate that the plasticity of membrane excitability associated
with control over stress can be attributed to an increase in Na+ and Ca2+
T-type conductances and an increase in the leak conductance. Using simulated
dendritic synaptic inputs we observed an increase in excitatory postsynaptic
summation and amplification resulting in elevated action potential output. This
realistic simulation suggests that control over stress enhances the output of
the PFC and offers specific testable hypotheses to guide future
electrophysiological mechanistic studies in animal models of resilience and
vulnerability to stress.
