SCENARIO 2: BLAME THE BRAIN STEM
Alternatively, hypersensitive or malfunctioning nerve cells in three nuclei in the brain stem might be the catalyst.
1. Parts of the brain stem, specifically the raphe nucleus, the locus coeruleus and the periaqueductal gray, behave abnormally.
2. The abnormal brain stem activity triggers spreading depression in the cortex or subcortex, thereby activating the trigeminal system.
3. In addition, the brain stem misbehavior can independently activate the pain pathways leading to the sensory cortex.
Illustration Credit: Tami Tolpa