Excert from "The tale of the dueling neurosurgeons"

The first clue for deciding between the functional and anatomical theories came from a Swiss chemist. In 1938 Albert Hofmann’s drug company was searching for new stimulants, and he began investigating some chemicals derived from a fungus. He soon drifted to other compounds but had a nagging feeling that the fungi had more to teach him. So on a Friday afternoon in April 1943, he whipped up a fresh batch of one chemical, called lysergic acid diethylamide (in German, Lyserg-Säure-Diäthylamid). During the synthesis he suddenly felt woozy and saw streaks of color. He later guessed he’d gotten some powder on his finger, then rubbed his eyes. But he wasn’t sure, so he tested his guess on Monday, April 19—forevermore known as Bicycle Day. He dissolved a tiny amount of powder, a quarter of a milligram, in a quarter shot of water. It had no taste, and down the hatch it went. This happened at 4:20 p.m., and although Hofmann tried to record his sensations in his lab journal, by five o’clock his handwriting had deteriorated into a scrawl. His last words were “desire to laugh.” Feeling unsettled, he asked his assistant to escort him home on his bicycle. It was quite a trip.

On the ride, the streaks of color reappeared before his eyes, and everything became elongated and distorted, as if reflected in a curved mirror. Time slowed down as well: Hofmann thought the trip took ages, but the assistant remembered furious pedaling. In his drawing room at home, Hofmann struggled to form coherent sentences, but finally made it clear that (for some reason) he thought milk would cure him. A neighbor woman patiently hauled bottle after bottle to him, and he chugged two liters that night, to no avail. Worse, Hofmann began having supernatural visions. His mind transmogrified the neighbor into a witch, and he felt a demon rise up inside him and clutch his soul. Even his furniture seemed possessed, trembling with menace. He felt certain he’d die right there on his couch.

Only hours later did he calm down, and he actually enjoyed the last hour. His eyes became veritable kaleidoscopes, with Fantasia-like fountains of color “exploding [and] rearranging and hybridizing themselves in constant flux.” It also pleased him, he later reported, that “every acoustic perception, such as the sound of a door handle or a passing automobile, became transformed into optical perceptions. Every sound generated a vividly changing image, with its own consistent form and color.” In other words, the drug produced synesthesia, something he’d never experienced.

Hofmann’s Lyserg-Säure-Diäthylamid eventually became known as LSD, and since then thousands of Phish and Grateful Dead fans have had similar experiences. Tripping on LSD obviously can’t change the brain’s hardwired circuits. LSD can interfere with neurotransmitters, however, and warp the information flowing through those circuits for a few hours. It’s like flipping your television from a Ken Burns documentary to a David Lynch nightmare sequence—the same circuitry is providing the picture, but the content is much wilder. This provides strong support for the functional theory of synesthesia. There’s some evidence that natural synesthetes still might have brains that are wired a little differently. But the experience of Hofmann and others suggests that we all might have a talent for synesthesia latent inside us, if only we could tap it.