Allodynia: Pain from something that normally does not hurt, like brushing your hair, caused by a sensitized nervous system. Learn more →

Allostatic load: The total wear and tear on the body from repeated or unresolved stress. Think of it as how full your bucket is. Learn more →

Aura: Temporary visual, sensory or speech symptoms that usually come before or with a migraine headache. Learn more →

Autonomic nervous system: The part of the nervous system that controls automatic functions such as heart rate, blood pressure and digestion. Learn more →

Brainstem: The base of the brain, connecting to the spinal cord. It controls basic functions and is active early in migraine attacks. Learn more →

Cerebellum: A brain region at the back of the head that coordinates movement, balance and eye movements. Learn more →

CGRP: Calcitonin gene-related peptide, a messenger molecule released in migraine that drives pain. Several newer medications block it. Learn more →

Chronic migraine: Headache on 15 or more days a month for more than 3 months, with migraine features on at least 8 of those days. Learn more →

Convergence: The ability of both eyes to turn inward together to focus on something close. Learn more →

Cortical spreading depression: A slow wave of nerve-cell activity followed by quieting that spreads across the brain’s surface. It is linked to aura. Learn more →

DAO (diamine oxidase): An enzyme in the gut that breaks down histamine from food. Learn more →

Episodic migraine: Migraine with fewer than 15 headache days per month. Learn more →

Gaze stability: Keeping your vision clear and steady while your head moves. Exercises for this are a core neurological therapy. Learn more →

Gepants: A class of medications that block the CGRP receptor, used for acute treatment or prevention. Learn more →

Histamine intolerance: Difficulty breaking down histamine from food, which can contribute to migraine, congestion and fatigue. Learn more →

HIT-6: The Headache Impact Test, a six-question survey measuring how headache affects daily life. Learn more →

Homocysteine: An amino acid that can rise when B vitamins are low. Higher levels are linked to migraine. Learn more →

HPA axis: The hypothalamus, pituitary and adrenal glands, the body’s main stress-response system. Learn more →

HPG axis: The hypothalamus, pituitary and gonads (ovaries or testes), which regulate sex hormones. Learn more →

Hypothalamus: A small brain region that controls sleep, hunger, hormones and body temperature. It is active early in migraine. Learn more →

Ketogenic diet: A very low-carbohydrate, high-fat diet. It is the most studied diet for migraine. Learn more →

Medication overuse headache: Worsening headache caused by taking acute headache medicines too often. Learn more →

Menstrual migraine: Migraine attacks linked to the start of the menstrual period and the drop in estrogen. Learn more →

MIDAS: The Migraine Disability Assessment, a questionnaire that counts days lost to migraine over 3 months. Learn more →

Mitochondria: The energy-producing parts of cells. Riboflavin, CoQ10 and magnesium support their function. Learn more →

Neuromodulation: Treatments that use electrical, magnetic or light energy to change nerve activity. Learn more →

Neuroplasticity: The brain’s ability to change and adapt with repetition and training. Learn more →

Postdrome: The “migraine hangover” phase after the headache, with tiredness and brain fog. Learn more →

Premonitory phase: Early warning symptoms such as yawning, cravings and neck stiffness, up to 48 hours before the headache. Learn more →

Proprioception: Your brain’s sense of where your body is in space. Learn more →

Saccades: Quick jumps of the eyes from one point to another. Learn more →

Sensitization: When the nervous system becomes more reactive, lowering the threshold for pain. Learn more →

Thalamus: A relay station deep in the brain that sends sensory information, including light, to other areas. Learn more →

The Harcourt Method: Dr. Harcourt’s simple, dynamic head-movement test used to identify directions of dysfunction and guide exercises. Learn more →

Trigeminal nerve: The main nerve carrying sensation from the face and head, central to migraine pain. Learn more →

Trigger point: A tender spot in a muscle that can refer pain elsewhere, including to the head. Learn more →

Triptans: A widely used class of acute migraine medications. Learn more →

Vagus nerve: The main “rest and digest” nerve. It can be stimulated non-invasively to treat migraine. Learn more →

Vestibular migraine: Migraine that causes vertigo or dizziness, sometimes without much headache. Learn more →

Vestibular system: The balance system in the inner ear and brain. Learn more →

VOMS: Vestibular/Ocular Motor Screening, a test of eye and balance function often used after concussion. Learn more →