In 1944 Leão expressed his theory of CSD, a well-defined wave of
neuronal excitation in the cortical gray matter spreading from the
site of origin at an average of 4 mm per minute (range 2–6 mm/
min).33 The ensuing cellular depolarization causes the primary cortical phenomena (aura phase), the basis of which is the release of potassium or glutamate from neuronal tissue that depolarizes adjacent
tissue, which in turn then releases more neurotransmitters and thus
propagates the CSD.
Positron emission tomography (