Pathophysiology is functional changes associated with or resulting from disease or injury and the study of those changes.
When related to Migraine attacks, the pathophysiology of a Migraine attack would mean the changes in how the brain and central nervous stem function when a Migraine is triggered and during the Migraine attack. We could discuss the pathophysiology of how the triggers themselves work -- what changes occur when we encounter a trigger. We could discuss the pathophysiology of a Migraine attack -- what happens to the blood vessels, the nerves and tissues surrounding the blood vessels, the levels of neurotransmitters such as serotonin and norepinephrine.
All of these discussions would be about the pathophysiology of Migraine, something that is still not fully understood. Researchers are making advances, however. The most recent article we published about Migraine research that was related to pathophysiology is Why Hangovers May Be Worse for Migraine Sufferers.