Re: stress

Damage to the dorsal motor nucleus occurs in PWP. However it is not involved with heart rate and stress response, that is located in the nucleus ambiguus of the vagus.
PWP also show massive loss of hypocretin/orexin neurons in the hypothalamus (pdf). I propose this is a likely mechanism by which the stress response in PWP is amplified:

Hypocretin-1 (Orexin-A) Facilitates Inhibitory and Diminishes Excitatory Synaptic Pathways to Cardiac Vagal Neurons in the Nucleus Ambiguus

Hypocretin-1 is a neuropeptide recently shown to be involved in autonomic regulation. Hypocretin-1 is expressed by hypothalamic neurons, which project to many regions of the central nervous system, including the nucleus ambiguus. One possible site of action of hypocretin-1 could be cardioinhibitory parasympathetic vagal neurons within the nucleus ambiguus. This study examines whether hypocretin-1 modulates inhibitory and excitatory postsynaptic currents in cardiac vagal neurons in the rat nucleus ambiguus. GABAergic, glycinergic, and glutamatergic activity to cardiac vagal neurons was examined using whole-cell patch-clamp recordings in an in vitro brain slice preparation. Hypocretin-1 (1 µM) produced a significant increase in the frequency and amplitude of both GABAergic and glycinergic inhibitory postsynaptic currents and a significant decrease in the frequency of glutamatergic excitatory postsynaptic currents. Application of tetrodotoxin (0.5 µM) blocked all of the responses to hypocretin-1, indicating the changes in neurotransmission with hypocretin-1 do not occur at presynaptic terminals but rather occur at the preceding GABAergic, glycinergic, and glutamatergic neurons that project to cardiac vagal neurons. The increase in GABAergic and glycinergic inhibitory postsynaptic currents, and the decrease in glutamatergic excitatory postsynaptic currents, could be mechanisms by which hypocretin-1 affects heart rate and cardiac function.

(I have never been able to speak in public. My heart would race and my vision would constrict and I was unable to see my notes. Until recently I couldn't even post on online forums, the stress would give me tics for days.)