How does vasodilation trigger migraine in the trigeminovascular system?

The trigeminovascular system is a physiological network involving the trigeminal nerve, cranial blood vessels, brain stem, thalamus, and cortex. Its main function is to transmit nociceptive signals that ultimately generate the perception of migraine pain. The process begins with dilation of meningeal arteries, leading to activation of neurons in the trigeminal ganglion, which propagate nociceptive signals to the brain stem. These signals then ascend to neurons in the thalamus and eventually reach the cortex, where they are processed and perceived as migraine pain.