  Migraine is a common disabling headache disorder characterized by recurrent
episodes sometimes preceded or accompanied by focal neurological symptoms
called aura. The relation between two subtypes, migraine without aura (MWoA)
and migraine with aura (MWA), is explored with the aim to identify targets for
neuromodulation techniques. To this end, a dynamically regulated control system
is schematically reduced to a network of the trigeminal nerve, which innervates
the cranial circulation, an associated descending modulatory network of
brainstem nuclei, and parasympathetic vasomotor efferents. This extends the
idea of a migraine generator region in the brainstem to a larger network and is
still simple and explicit enough to open up possibilities for mathematical
modeling in the future. In this study, it is suggested that the migraine
generator network (MGN) is driven and may therefore respond differently to
different spatio-temporal noxious input in the migraine subtypes MWA and MWoA.
The noxious input is caused by a cortical perturbation of homeostasis, known as
spreading depression (SD). The MGN might even trigger SD in the first place by
a failure in vasomotor control. As a consequence, migraine is considered as an
inherently dynamical disease to which a linear course from upstream to
downstream events would not do justice. Minimally invasive and noninvasive
neuromodulation techniques are briefly reviewed and their rational is discussed
in the context of the proposed mechanism.
