Art, its creators will tell you, is the result of introspection, the often painful process of digging into the past, into dreams of what might be and nightmares of what was.

The painter Marc Chagall, for example, never forgot the tiny, mud-spattered village in Eastern Europe where he grew up. Images of it cropped up in the corners of his works throughout his life.

William Faulkner could never have produced his doomed Southern aristocrats without his family’s haunted past, nor could Kurt Vonnegut have written about the horrors of war without the experience of being a soldier.

But what happens to an artist whose memory is drained, who has almost nothing to draw on?

A small but intriguing show at the Walters Art Museum in Baltimore explores that mystery by looking at the work of a woman who suddenly lost most of her past.

In 2007, Lonni Sue Johnson was an accomplished illustrator, and a musician, pilot and farmer. She had done half a dozen covers for the New Yorker magazine. Her brightly colored illustrations brimmed with gentle humor and puns.

On Dec. 30, a snowy morning, a farmer stopped by Johnson’s organic dairy farm in Upstate New York. He noticed she was confused and unable to take her eyes off the mouse of her computer. He called a medical worker down the road, who took one look at Johnson and rushed her to a hospital in Cooperstown. The 57-year-old artist was a wreck. She only stared at her hands — first one, and then the other.

A virus had invaded Johnson’s brain. Before doctors could halt the encephalitis, it ravaged parts of her hippocampus, which is crucial to memory formation. Profound amnesia engulfed her.

Three and a half years after her illness, Johnson has few memories. More devastating, she lost the ability to form new ones. Unlike the amnesia that is suddenly cured in so many Hollywood movies, Johnson’s inability to form new memories cannot be repaired. The present is constantly slipping away, but she has not lost her soft humor. But had she lost her ability to be an artist?

At first, she had trouble walking, talking and eating. The condition affected her ability to reason as well. Although she never forgot her own identity, she recognized only a few people: her mother, her sister and a few faces she had known as a child.

Art had been her window on the world. Her mother and grandmother were artists. She’d had a 31-year career. But after her illness, she couldn’t draw. Her pencil hovered just above the paper, never touching down. The window had slammed shut.

What happened next is the reason to visit the Walters show.

With Johnson unable to draw, her mother, Margaret Kennard Johnson, tried having her copy simple shapes. Lonni Sue, who, as an illustrator, hated to copy anything from anybody, put pen to paper. She reproduced the shapes exactly.

Then came another breakthrough: Margaret drew a squiggly line on a paper with a red pen. She asked Lonni Sue to complete the drawing. When Lonni Sue’s blue pen touched down, a cat emerged.

Another turning point came six months later. A puzzle-maker, who was a friend of the family, dropped off three word-search books. Lonni Sue had rebuilt her vocabulary, and she devoured the exercises.

She finished the books and wanted more. Before her mother could fetch some, Lonni Sue started making grids with words hidden in them. Thousands of puzzles poured out of her. Wearing thin the pages of a paperback dictionary, she created elaborate word lists, then puzzles from the lists and then images from the puzzles. A grid of words for things that hang in the closet took the shape of a coat hanger. Words related to trousers formed a pair of pants. Her vocabulary seemed to open a new door for her creativity.

Enter Barbara Landau. She had gone to high school with Lonni Sue in the Princeton, N.J., area. (“She was brilliant,” Landau remembers.) Today, Landau is an expert on cognitive science at Johns Hopkins University. She had followed Lonni Sue’s career as an artist for years and now, with Hopkins colleague Michael McCloskey, she explored Lonni Sue’s amnesia intensively. It was Landau who brought Lonni Sue’s art to the Walters.

Scientists often work with people who have lost the use of part of the brain to learn how the normal brain works.

After working with Lonni Sue, Landau concludes: “If we think that art and creativity have to be rooted in what we know about ourselves or what we remember about ourselves, that clearly is not the case.”

Lonni Sue has been full of surprises. She can remember how to fly an airplane — “It’s like dancing in the sky,” she said in an interview — but she can’t remember the death of her father.

She can’t recognize art she treasured before her illness — “Starry Night” by Vincent van Gogh, for example. Yet she can instantly recognize her own past work.

She can’t remember that she was married for 10 years, but she can remember how to play Bach suites on her viola. But if, as she’s putting her instrument away, her mother thanks her for playing, she’s likely to look astonished and say, “Oh, did I play?”

She cannot produce the kind of finished art she once drew, but her work shows flashes of her old skill as well as her characteristic whimsy and puns.

“When you draw a drawing, you can draw people in,” she says.

We often think that human memory is some sort of internal hard-drive, humming away inside the skull. But it’s not, Landau says. “Memory is not just one thing; it’s many things.”

She and others point to this collection of 36 artworks — some from before the encephalitis and more from after — as a prism for looking at a few of the riddles of the mind, though she says it will leave observers with more questions than answers: questions about the nature of memory and of creativity, and what an artist needs to make art.

Lonni Sue and her family live near Princeton. She seems happy and cheerful, although she says she misses flying.

She is rarely without her worn dictionary and a 4-inch stack of white typing paper, often stopping to capture a fleeting thought on a page before it flies away. She rises at 5:30 a.m. and spends almost all her waking hours drawing and creating puzzles.

Her family has kept everything she has produced since her illness in hopes it can offer insight into the relationship between neural science and creativity.

So far, it’s a stack of paper 15 feet thick.

Her sister Aline says, “Art is the cardinal part of her life.” Aline believes it functions as an external memory drive that keeps Lonni Sue’s ideas from floating away.

“Time goes too fast,” Lonni Sue says.

Her most recent puzzle is an alphabetical Noah’s Ark, taking on words two by two, beginning with “Absolutely airplanes beautifully bring . . .” Lonni Sue turns the list into a little song, which she sings in a pitch-perfect, lilting soprano.

Her final pair is “zestfully zooming.”

John Pancake was arts editor of The Washington Post from 1996 to 2008 and spent the past three years in Ukraine and Taiwan. He lives in the Shenandoah Valley. His last piece for The Washington Post was about his quest to see Shakespeare’s worst play.

Puzzles of the Brain: An Artist’s Journey Through Amnesia

at the Walters Art Museum through Dec. 11 (10 a.m.-5 p.m. Wednesdays-Sundays). Produced in partnership with the Cognitive Science Department of Johns Hopkins University. The museum is at 600 N. Charles St., Baltimore. 410-547-9000 or