American Scientist

A few centuries ago, people who described an episode of strangely skewed vision followed by a throbbing headache might be told they had received a message from heaven, or else they had been possessed by an evil spirit. A generation ago, similar tales of hallucinations and pain were often received with neither fear nor awe but simply exasperation. The writer Joan Didion found that her accounts of migraine sometimes met with reactions little short of disdain, “for I had no brain tumor, no eyestrain, no high blood pressure, nothing wrong with me at all. I simply had migraine headaches, and migraine headaches were, as everyone who did not have them knew, imaginary.”

On the contrary, those who have experienced them know that migraines are all too real. Making sense of them is a major challenge, however. They are made even more baffling by the fact that the headache is not their only manifestation. Migraines are often preceded or accompanied by visual hallucinations. Arriving suddenly out of a clear blue sky, a migraine aura—a set of shimmering, flashing, weird perceptions—is bound to seem inexplicable, even frightening. This was certainly the case for eminent neurologist Oliver Sacks, whose first migraine occurred when he was only three or four years old. The incident left an indelible memory:

“I was playing in the garden when a brilliant, shimmering light appeared to my left—dazzlingly bright, almost as bright as the sun. It expanded, becoming an enormous shimmering semicircle stretching from the ground to the sky, with sharp zigzagging borders and brilliant blue and orange colors. Then, behind the brightness, came a blindness, an emptiness in my field of vision, and soon I could see almost nothing on my left side. I was terrified—what was happening? My sight returned to normal in a few minutes, but those were the longest minutes I had ever experienced.“

Fortunately for young Oliver, his mother immediately recognized the condition. As a migraine sufferer herself, and a trained physician, she could assure him he would soon be good as new. She explained he had experienced “a sort of disturbance like a wave” passing across a part of his brain, temporarily distorting his senses.

Years later, Oliver Sacks wrote a book, Migraine, and a number of related articles that greatly increased the public understanding of migraine—not just the headache but also the aura and other characteristic symptoms—as an illness, and a fairly common one at that. According to figures from the World Health Organization, as many as 11 percent of all adults suffer from this condition, which affects their quality of life and interferes with work and social activities. The toll on the affected individual amounts to an estimated 1.3 years lost to disability over a lifetime.

In trying to identify the cause of migraines and the sensory havoc that comes with them, patients and healthcare professionals have pointed to a great variety of factors: coffee, red wine, aged cheese, sunlight, exercise or lack of exercise, fluctuating hormone levels, chronic stress. Although a discrete episode of migraine might be triggered by any of these, or even by no apparent factor at all, the underlying susceptibility to migraines seems to be encoded in the genome. In studies focusing on the so-called classic manifestation, migraine with aura, researchers have identified mutations in several genes that are involved in the release and uptake of two important signaling molecules in the synapses between brain cells.

One of these chemical signals, or neurotransmitters, is serotonin, which helps regulate sleep and mood and is also involved in the perception of pain. The other neurotransmitter, glutamate, serves as an excitatory signal, enabling the physical processes in the brain that underlie learning and memory. Too much excitement can be dangerous, however: Although under normal circumstances glutamate acts as the “on” signal for many brain activities, over-exposure to glutamate may cause receptor cells to shut down altogether for a time, or even die.

A recent study in Nature Genetics suggests that if neurons at the receiving end of a glutamate signal do not perform efficiently, an accumulation of glutamate in the synapses may help bring on migraine attacks. The wave of hyper-excitement followed by inactivity spreads across the cerebral cortex and gradually disperses like ripples on the surface of a pond, in a feature known as cortical spreading depression. Depending on which regions of the brain it affects, cortical spreading depression can wreak mischief on the senses in myriad ways, in addition to the most common visual auras. Journals of neurology abound with case histories of hallucinatory sounds, illusory odors (usually unpleasant, alas), dizziness, tingling, numbness, or out-of-body experiences.

Jagged Edges and Blank Spots

Describing a subjective visual experience is difficult for most migraine patients, and challenging for researchers to describe accurately in the scientific literature as well. Fortunately, artists have found a great many ways to record the influence of migraine aura in their works, and these depictions have proved useful for characterizing specific effects of the cortical spreading depression on the intricate circuitry in the brain that allows us to see.

Take the sketch on the opening page of this article, for example. Lewis Carroll, who was known to suffer from terrible headaches, drew this frontispiece sometime around 1855 for a magazine called Mischmasch that the Carroll family produced from time to time. Playful and amusing at first glance, the sketch also has an alarming side—specifically, the right side, where the figure is missing a hand, a shoulder, and a portion of his head. These areas are not indicated in a tentative way, nor are they obscured. They are simply blank, as if to say, ”Nothing to see here.” And in fact, Carroll may have seen nothing there, even though he surely was aware that there should have been more to see.

Psychiatrist Klaus Podoll and his coauthor Derek Robinson, in their book Migraine Art: The Migraine Experience from Within, point out that the blank area in the sketch offers a clinically accurate depiction of the migraine symptom known as a scotoma—a blind spot or defect in the field of sight, one of many tricks that migraine aura can play on the visual system.

The negative scotoma in Carroll’s drawing has as its counterpart the positive scotoma, as seen on this page in a 1969 painting by Giorgio de Chirico called The Return to the Castle. (The poet Guillaume Apollinaire, a friend of the painter and a fellow surrealist, has suggested that de Chirico often worked under the influence of migraine.) Here the blind spot appears, to dramatic effect, in the shape of two figures that are clearly identifiable, down to the detail of the horse’s reins and the plume on the knight’s helmet. At the same time, the dark shape blocks the view of a large part of the serene landscape. In opposite ways, Carroll’s drawing and de Chirico’s painting both call attention to what cannot be seen in the midst of a migraine aura; the viewer, willingly or not, shares in their experience.

Migraine-inspired art emerged in the 1970s as a distinct subgenre with the launching of a foundation for its display and for its wider recognition (www.migraine-aura.com). National and then international art competitions soon followed; by 2006, an Internet survey of such contests by Podoll found entries from 450 artists representing 25 countries. Podoll concludes, “Far from being being just relevant as an art-inspiring factor in the context of Migraine Art contests, migraine experiences can be shown to act as a source of inspiration in a considerable number of contemporary artists.”

The most common feature of a migraine aura—some clinicians call it “almost diagnostic” of the migraine experience itself—is the appearance of parallel zigzag forms across one’s field of sight. These lines are termed fortification patterns, for their resemblance to the walls built around medieval towns to defend them from invasion. (The more impressive term “teichopsia,” from the Greek for “town-wall vision,” comes to much the same thing.)

Pikes, Stars, and Shimmering Lines

To some sufferers, the fortification lines appear to march in military fashion; in his diaries, Carroll records an “odd optical affection of seeing moving fortifications.” He also alludes to difficulties with the vision in his right eye, followed in at least one instance by a headache. Carroll does not seem to have gone public with his migrainous experiences, and perhaps he never even consulted a physician about them. Neverthless, he managed to transplant them into the minds of millions of readers, and he continues to pull off this feat long after his death.

Diagnostic terminology has followed the lead of Carroll’s art. A paper recently published in Neurology tells the story of how the term “Alice in Wonderland syndrome” came into use in the 1950s for the paroxysmal body image illusions that can constitute one kind of migraine aura.

Regardless of the medium in which they are created, art and literature have long served as valuable sources for investigating the neural activity that produces a migraine aura. As the cortical spreading depression propagates across the cortex, the scotoma or fortification pattern appears to move. The protagonist in de Chirico’s autobiographical novel, Hebdomeros, suffers a migraine attack in which he sees strange shapes that “all went away in a corkscrew formation, or else in regular zigzags, or else in strictly perpendicular fashion resembling pikes carried by a disciplined troop.”

Among the earliest migraine sufferers to record her experience in pictures as well as text was Hildegard von Bingen, a 12th-century German abbess, philosopher, and composer. Like so many migraine sufferers, she was bewildered and frightened at first by the unearthly sights of her migraine aura. Their source was clear to her, however. As someone who from the age of eight spent her life in religious orders, Hildegard naturally saw these visions as glimpses of the divine.

Of one episode, she writes: “I saw a great star, most splendid and beautiful, and with it an exceeding multitude of falling sparks with which the star followed southward . . . and suddenly they were all annihilated, being turned into black coals . . . and cast into the abyss so that I could see them no more.” The jagged edges of a star, flashes of light from moving sparks, and the subsequent blackness—to recognize all these perceptions as typical of a migraine aura does not contradict the profoundly spiritual nature of this sufferer’s migraine experiences. Although she did not receive a formal education, Hildegard kept up with the best scientific thinking of her time; she read widely, developed a theory of cosmology, and was known as a gifted herbalist. Simply, the visions of migraine aura carried a religious meaning for her because that was the form her mind imposed on them.

In similar fashion, Carroll’s incongruously cheerful sketch illustrates the quirky mind of the creator of Alice in Wonderland, and de Chirico’s painting conveys the surrealist milieu in which he lived and worked. Friedriech Jolly, a German neuroloist and psychiatrist who was himself a migraine sufferer, combined personal experience and a clinical turn of mind in illustrating the flickering zigzags of migraine aura, which he believed to be “a malady that affected primarily the Learned Classes,” on account of their extensive reading.

Bringing the story of migraine aura illustration up to date are the ever-changing collections that now proliferate on the Internet, as well as in artistic competitions large and small. The example below at right, by painter and writer Petrie Serrano, shows wavy, sinuous lines in place of the time-honored zigzags, but at the same time it re-creates other effects that are unhappily familiar to many migraine sufferers: a sense of movement and of disorientation.

With an incidence calculated by the World Health Organization to be about 3,000 migraine attacks per million people per day, it is hardly surprising that artistic depictions of migraine aura should look so varied even as they contain many of the same basic elements. What is surprising—what is perhaps even wonderful—is that the artistic mind can manage again and again to infuse a chaotic, painful experience with meaning and occasionally, somehow, with beauty.