What Causes Migraines in Humans At The Brain Level?

Discover what causes migraines in humans—from brain chemistry to genetic factors, hormones, stress, and environmental triggers. Science-backed answers.

I'll never forget my first migraine. I was 22, sitting in a meeting, when suddenly the fluorescent lights seemed to pierce directly into my skull. Within minutes, I saw a shimmering zigzag pattern spreading across my vision like a broken TV screen. Then came the nausea. Then the pain—a throbbing, pulsing agony that felt like someone was rhythmically driving a spike into my temple.

I thought I was having a stroke. Turns out, I'd joined the 39 million Americans who experience migraines—a neurological condition that's simultaneously common and deeply misunderstood.

Here's what most people don't realize: migraines aren't "just bad headaches." They're a complex neurological disorder involving your brain, nervous system, and blood vessels. Understanding what causes migraines in humans requires diving into genetics, brain chemistry, triggers, and the intricate ways your nervous system can essentially short-circuit.

If you've experienced migraines, or you're trying to understand them for someone you love, let me walk you through the science of what's actually happening inside your head.

What Actually Causes Migraines at the Brain Level?

To understand migraine causes, we need to start with what's happening inside your brain during an attack.

Migraines involve a cascade of neurological events:

1. Brain Hyperexcitability

People with migraines have brains that are unusually sensitive to stimulation. Your neurons (brain cells) are more reactive to triggers than in people without migraines.

Think of it like having a car alarm that goes off at the slightest vibration. Your brain's alarm threshold is set lower—things that shouldn't trigger a response, do.

2. Cortical Spreading Depression

During a migraine with aura (those visual disturbances I experienced), something called cortical spreading depression occurs. This is a wave of electrical activity that slowly spreads across your brain's surface, followed by temporary loss of function.

It's like a power surge followed by a brief blackout—except it's happening in the visual processing center of your brain, which is why you see weird patterns or blind spots.

3. Activation of the Trigeminal Nerve System

Your trigeminal nerve is the main pain pathway from your face and head to your brain. During migraines, this system activates inappropriately, releasing inflammatory substances around your brain's blood vessels.

This creates the throbbing pain you experience—it's your brain's pain signaling system gone haywire.

4. Neurotransmitter Imbalances

Several brain chemicals play crucial roles in migraine causes:

Serotonin: Levels drop during migraine attacks, affecting pain processing and blood vessel constriction. CGRP (Calcitonin Gene-Related Peptide): Elevated during attacks, causes blood vessel dilation and pain signal transmission. Modern migraine medications (CGRP antagonists) specifically target this. Dopamine and glutamate: Also involved in the complex cascade of migraine brain chemistry.

5. Blood Vessel Changes

Contrary to old theories, migraines aren't caused by blood vessels constricting then dilating. Instead, the blood vessel changes are part of the neurological cascade—a consequence, not the primary cause.

Your brain chemistry goes haywire first, which then affects blood vessels, which amplifies the pain signals.

Are Migraines Genetic? The Family Connection

Yes, migraines definitely run in families—and the genetic component is strong.

The genetic facts:

If one parent has migraines, you have a 50% chance of developing them. Having two parents with migraines raises the chance to around 75%. Twin studies show migraine heritability is 40-57%.

Multiple genes are involved, not just one "migraine gene." These genes affect how your brain processes pain, responds to inflammation, and regulates neurotransmitters.

What you inherit:

You don't inherit the migraine attacks themselves—you inherit a brain that's more susceptible to them. You inherit lower thresholds for trigger activation. You inherit variations in serotonin receptors, ion channels, and pain pathways.

Think of it like inheriting a predisposition for allergies. You inherit the tendency to overreact to certain stimuli—in this case, your brain overreacting to triggers that wouldn't affect someone without the genetic susceptibility.

My mother gets migraines. Her mother got them. I never stood a chance. But knowing it's genetic also means I can be proactive about identifying and managing my triggers.

Common Migraine Triggers: What Sets Off Attacks

Here's a critical distinction: genetic causes create the underlying susceptibility, but triggers are what actually set off individual attacks.

You can't change your genetics, but you absolutely can manage triggers.

Stress and Emotional Factors

Stress is the single most commonly reported migraine trigger, affecting up to 80% of migraine sufferers.

Why stress causes migraines:

• Releases cortisol and other hormones that affect brain chemistry
• Causes muscle tension, particularly in neck and shoulders
• Disrupts sleep patterns
• Changes eating patterns

The weekend migraine phenomenon: Many people get migraines when they finally relax after a stressful week. The rapid drop in stress hormones can trigger an attack—your brain doesn't handle the transition well.

Anxiety disorders and migraines often coexist, creating a vicious cycle where anxiety triggers migraines, and fear of migraines causes more anxiety.

Solutions: CBT-based stress management apps and mindfulness programs help break this cycle. Regular exercise and proper sleep create resilience against stress triggers.

Hormonal Changes (Particularly in Women)

Hormones are major migraine causes in women. Approximately 60% of women who experience migraines report that their attacks are associated with their menstrual cycle.

Why hormones cause migraines:

• Estrogen fluctuations affect serotonin receptors
• The natural drop in estrogen before menstruation is a common trigger
• Birth control pills, pregnancy, and menopause all affect migraine patterns

Menstrual migraines typically occur 2 days before through 3 days after menstruation starts. They're often more severe and longer-lasting than non-hormonal migraines.

Pregnancy's effect: Many women experience fewer migraines during pregnancy (higher, stable estrogen), but migraines often return or worsen postpartum.

Management: Hormone-focused care with gynecologists can help, including mini-preventive medications around menstruation or adjusting contraceptives.

Sleep Disruptions

Both insufficient sleep and excessive sleep can bring on migraines. Your brain likes consistency.

Sleep-related triggers:

• Sleeping fewer than 6 hours or more than 9 hours can also trigger migraines.
• Irregular sleep schedules (shift work, jet lag)
• Poor sleep quality
• Sleep apnea (often undiagnosed in migraine sufferers)

Solutions include using white noise machines, wearing sleep masks, and keeping consistent bed and wake times—even on weekends. Sleep tracking apps help identify patterns.

Food and Drink Triggers: The Controversial Category

Food triggers are highly individual and often overstated. Not everyone reacts to the same foods, and systematic elimination diets can lead to unnecessary restrictions.

Common food-related migraine triggers:

Alcohol: Particularly red wine, which contains tyramine and histamine. Triggers about 30% of migraine sufferers.

Caffeine: Both consumption and withdrawal can trigger attacks. Regular caffeine users who suddenly skip their morning coffee often get migraines. The key is consistency—regular amounts help some people, irregular use hurts.

Aged cheeses and processed meats: Contain tyramine, which affects blood vessel constriction and neurotransmitter release.

MSG and food additives: Some people react to monosodium glutamate and artificial sweeteners.

Chocolate: Often blamed, but the craving for chocolate might actually be an early migraine symptom rather than a cause.

Skipping meals: Causing blood sugar drops and dehydration—both migraine triggers.

The truth about food triggers:

Most people don't have food triggers. Those who do usually have 1-3 specific culprits, not 20. Food triggers work in combination—you might tolerate wine OR aged cheese, but not both together.

Approach wisely: Use food and additive tracking guides to systematically test suspected triggers. Don't eliminate entire categories without evidence they're actually affecting you.

Environmental and Sensory Triggers

Light Sensitivity (Photophobia)

Bright lights and screen time are major environmental migraine triggers.

Why light causes migraines:

• Stimulates light-sensitive nerves connecting to pain pathways
• Particular wavelengths (blue-green light) are most triggering
• Flickering or pulsing lights overstimulate visual cortex
• Contrast and glare exacerbate the problem

Modern challenges:

• Computer screens and smartphones emit high levels of blue light
• LED lights flicker at frequencies that can trigger attacks
• Fluorescent office lighting is particularly problematic

Solutions:

• FL-41 tinted migraine glasses filter triggering wavelengths (clinically proven effective)
• Blue light-blocking screen filters for devices
• Smart bulbs with adjustable color temperature
• Polarized sunglasses for outdoor protection
• Take regular screen breaks (20-20-20 rule: every 20 minutes, look 20 feet away for 20 seconds)

Weather and Barometric Pressure Changes

About 50% of migraine sufferers report weather sensitivity, particularly to:

Barometric pressure drops: Before storms or weather fronts. Temperature extremes, such as very hot or very cold weather, can also trigger migraines. High humidity: Creates additional physiological stress. Rapid changes: Quick shifts in any weather parameter.

Why weather triggers migraines:

Barometric pressure changes affect the pressure in your sinuses and blood vessels. Temperature and humidity affect hydration status and blood flow. Weather systems may affect oxygen and ion concentrations in the air.

Management: Weather alert apps focused on barometric pressure provide early warning. Stay hydrated, rest more on high-risk days, and discuss preventive medication timing with your doctor.

Noise and Sensory Overload

Loud, repetitive, or high-pitched noises can trigger or worsen migraines. Concert halls, construction sites, loud restaurants—all potential trigger environments.

Solutions: Earplugs or noise-dampening headphones in loud environments. Take breaks from overstimulating settings.

Lifestyle Factors That Cause or Worsen Migraines

Dehydration

Even mild dehydration can trigger migraines. Your brain tissue is 73% water—when you're dehydrated, it literally shrinks slightly, pulling on pain-sensitive membranes.

Prevention: Use large water bottles with time markers to track intake. Electrolyte drinks help during exercise or hot weather.

Physical Exertion

Exercise can both help prevent migraines (regular moderate activity) and trigger them (sudden intense exertion, especially in hot weather).

Exertional migraines occur during or after physical activity, likely due to blood flow changes and dehydration.

Solution: Start regular exercise programs with low-impact, gradually increasing intensity. Stay hydrated, warm up properly, and avoid exercising in extreme heat.

Posture and Neck Problems

Poor posture, particularly forward head position from computer work, creates muscle tension that can trigger migraines.

Solutions: Ergonomic workstation tools including adjustable monitors, supportive chairs, and regular posture breaks.

Difference Between Causes and Triggers

This distinction is crucial for managing migraines effectively:

Aspect	Underlying Causes	Triggers
What it is	Brain susceptibility	Factors that set off individual attacks
Can you change it?	No (genetic predisposition)	Yes (many are modifiable)
Examples	Genetics, brain hyperexcitability	Stress, foods, sleep, light, weather
Treatment focus	Preventive medications	Trigger avoidance and management

Your genetics load the gun. Triggers pull it.

You can't change your genetic susceptibility, but identifying and managing your personal triggers gives you significant control over attack frequency and severity.

Migraine Aura and Sensory Symptoms

About 25-30% of people with migraines experience aura—warning symptoms that typically occur 10-60 minutes before head pain starts.

Common aura symptoms:

• Visual disturbances (zigzag lines, blind spots, shimmering)
• Sensory changes (tingling, numbness in hands or face)
• Speech difficulties (trouble finding words)
• Vertigo or dizziness
• Rarely: temporary weakness or confusion

Why some people have aura:

Aura is caused by that cortical spreading depression we discussed earlier—the wave of electrical activity across your brain. Not everyone with migraines experiences this particular neurological phenomenon.

Having aura doesn't mean your migraines are worse or better—it's just a different manifestation of the same underlying condition.

Important: If you suddenly develop new aura symptoms, especially after age 50, seek medical evaluation. While usually harmless, new neurological symptoms always warrant assessment.

Managing Migraine Causes and Triggers

Understanding what causes migraines in humans empowers you to take action. Here's your comprehensive approach:

1. Track Your Patterns

Use migraine and headache tracking apps to log:

• Date, time, duration of attacks
• Severity (1-10 scale)
• Symptoms experienced
• Potential triggers (food, sleep, stress, weather)
• Medications taken and effectiveness

Over time, patterns emerge. You might discover your migraines cluster around your period, follow poor sleep, or consistently occur on stressful work days.

2. Acute Treatment

Prescription/OTC migraine medications taken early in an attack can abort or significantly reduce severity:

• Triptans: Target serotonin receptors
• CGRP antagonists (gepants): Block the CGRP pathway
• NSAIDs: Reduce inflammation

Take medication at the first sign of migraine, not when pain is severe. Early treatment is dramatically more effective.

3. Preventive Medications

If you have frequent migraines (4+ per month), preventive medications reduce brain sensitivity so triggers are less likely to cause attacks:

• Beta-blockers
• Antiepileptic drugs (topiramate)
• Antidepressants (amitriptyline)
• CGRP monoclonal antibodies (monthly injections)

4. Non-Pharmaceutical Prevention

Nutraceuticals with evidence:

• Magnesium (400-600mg daily)
• Riboflavin/Vitamin B2 (400mg daily)
• Coenzyme Q10 (300mg daily)

These have moderate evidence and fewer side effects than prescription preventives. Use under medical supervision.

5. Trigger Management

Based on your tracking:

• Maintain regular sleep schedules
• Manage stress with CBT or mindfulness apps
• Wear FL-41 glasses and use blue light filters
• Stay consistently hydrated
• Eat regular meals
• Limit or time caffeine intake consistently
• Create a low-trigger environment when possible

6. Lifestyle Modifications

• Regular moderate exercise (with gradual warm-up)
• Ergonomic workspace setup
• Stress reduction techniques
• Limit screen time and take breaks
• Maintain healthy weight
• Avoid smoking

7. Medical Devices

Wearable neuromodulation devices (vagus nerve stimulators, transcutaneous trigeminal stimulators) offer non-drug options for some patients.

When to Seek Emergency Care

Most migraines, while miserable, aren't dangerous. However, seek immediate medical attention if you experience:

• Thunderclap" headache: Sudden, severe, reaching maximum intensity in seconds to minutes
• Headache accompanied by fever and a stiff neck: This may be a sign of meningitis.
• Headache after head injury: Even if injury seemed minor
• New neurological symptoms: Weakness, vision loss, confusion, difficulty speaking
• Headache with fever and a stiff neck: This could indicate meningitis.
• Change in your usual migraine pattern: Especially if over 50

These symptoms might indicate serious conditions requiring immediate evaluation.

The Bottom Line

What causes migraines in humans is a complex interaction between genetic susceptibility, brain chemistry, and environmental triggers. You inherit a nervous system that's hyperexcitable and prone to overreacting to stimuli. Various triggers—stress, hormones, sleep changes, lights, weather, foods—can then set off the neurological cascade that becomes a migraine attack.

While you can't change your genetic predisposition, you have enormous control over trigger management. Through careful tracking, lifestyle modifications, appropriate medications, and trigger avoidance, most people can significantly reduce migraine frequency and severity.

The key is understanding that migraines are a legitimate neurological condition—not character weakness or "just stress." Armed with knowledge about your personal causes and triggers, you can work with your healthcare team to develop an effective management strategy.

My migraines haven't disappeared, but understanding what causes them transformed my life. I know my triggers. I medicate early. I've made lifestyle adjustments. And those debilitating attacks that used to derail me for days? Now rare exceptions rather than regular occurrences.

That same relief is possible for you.

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Experiencing frequent migraines? Start tracking patterns with a migraine app, identify your personal triggers, and schedule an appointment with a neurologist or headache specialist. Effective management strategies exist—you don't have to suffer through migraines alone.

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