When scientists met a woman with amnesia named Lonni Sue Johnson, they were astonished by her. It was not so much what she could no longer remember, but the things she could not forget. Johnson is still unable to recall her own wedding day but she can tell you how to fly a plane. In 2007, viral encephalitis destroyed her hippocampus, a brain region that encodes new memories and retrieves old ones. The infection left her with severe retrograde amnesia, an inability to remember events that occurred before her illness. Prior to the onset of amnesia, she was a licensed pilot, an accomplished violist, and a professional artist, having created six covers for the New Yorker and contributed illustrations to more than 50 books. She can no longer recognize famous pieces of music, but she knows how to produce a harmonic on a viola.
“One of the most-striking things about her is that she retained a lot of knowledge about areas in which she had long-lived expertise,” says Dr. Barbara Landau, professor of cognitive science and neuroscience at Johns Hopkins University. The background knowledge has vanished, but she holds on to technical details. “She could tell us things like how to bow a viola and which brushes are used to achieve certain effects on paper.”
Nearly a decade later, her case continues to puzzle researchers. Johnson hasn’t driven a car, flown an airplane, or painted in years, and only occasionally plays music. Yet, she is surprisingly articulate and full of information about her pre-illness capabilities. Her odd pattern of what she can recall defies conventional thinking about memory.
Scientists have long believed that two different long-term memory systems are at work in the brain when we learn a skill. One is declarative, enabling you to remember general facts about the world or your personal history; the other is non-declarative or procedural, also known as muscle memory. Procedural memory, such as learning how to ride a bike or tie your shoes, doesn’t rely on conscious recall. Once you’ve learned how to do those things, they become habit.
Johnson challenges that divide. Landau has worked with her for years and published a series of articles exploring her cognitive capabilities. In a recent paper, she suggests that Johnson’s abilities may even point to a new type of memory. Could there be a blended form of memory that has gone unnoticed?
To some extent, Johnson’s case parallels that of Henry Molaison, a patient known widely as H.M. After surgeons removed his hippocampus to stop recurring seizures, H.M. lost his ability to form new memories. His experiences informed much of what we know about memory, including the role of the hippocampus.
“The hippocampus hooks pieces of information together,” says memory expert Dr. Lynn Nadel, professor of psychology and cognitive science at the University of Arizona. It sorts the pieces and “links and retains connections between them over time.” Without a hippocampus, you might still learn, but you won’t remember.
Johnson presents a perplexing contradiction. In a 2014 study that Landau participated in, Johnson was unable to recognize basic statistical patterns, performing worse than a young child. Yet she can learn new music, a technical feat requiring specific knowledge of music that should be out of her reach. H.M., too, had unusual capabilities. He didn’t recognize his own grandchildren, but he could learn procedural skills such as drawing. When researchers gave him a tricky drawing task, he improved on later attempts, despite having forgotten that he had already taken the test.
Landau believes that Johnson’s predicament could point toward a special category within declarative knowledge. Perhaps there is a certain type of factual knowledge, one that is more closely intertwined with skills.
“In light of all her losses in areas of general knowledge, it was really surprising that she had retained so much knowledge in areas in which she had expertise,” admits Landau. It seems as if some memories could be more deeply embedded in the brain.
Landau suspects that skills and knowledge may interact more closely than previously thought. She refers to a 2013 study on elite athletes by researchers at Yale and Johns Hopkins universities. The authors of that paper suggest that expert knowledge could lead to expert skills. For example, tennis players need to recall facts such as how their grip alters the racket angle or how spin affects the ball’s bounce.
Perhaps the ongoing exchange between body and mind leads to something special. This could mean there might be a specific category of memory that the brain treats differently.
BLURRING THE LINES
To find out more about Johnson’s cognitive abilities, Landau recently examined her recall of facts related to her former activities. Together with her colleagues Emma Gregory, Mike McCloskey, and Zoe Ovans, she tested Johnson’s knowledge of driving, flying, painting, and playing the viola and compared her to professionals and novices in those fields. Their findings were published in Cognitive Neuropsychology.
The series of tests included up to 88 questions dealing with areas in which she had expertise. The researchers asked questions such as: “When flying, how would you maneuver the aircraft to recover from a stall?” and “Where are the rudder controls located in the cockpit?” and “When playing pizzicato what do you pluck the strings with?” and “What would you do to the paper before you paint if you wanted the colors to ‘flow out?’”
The results were startling. Johnson can no longer identify well-known artworks, such as Van Gogh’s “Starry Night.” Nor does she recognize Beethoven’s Fifth Symphony or the tune of “Happy Birthday.” Yet she can describe in detail how to prepare a watercolor palette or explain the purpose of a viola’s bridge.
“She had a remarkable amount of knowledge, not only about performance, but also about viola bows, the properties of watercolor pigments and the details about airplane equipment,” Landau recalls. Her scores were not as high as professionals when it came to skills like flying and playing the viola. On watercolor painting, however, the former professional artist scored higher than the experts.
Their findings suggest that the division between memory types may not be as wide as it sometimes seems. “We’re not trying to question the distinction between declarative and procedural memory,” says Landau. “But it does blur the lines.”
It also reminds us how little we know about our minds. It may be tempting to think that the brain houses different types of memory within separate regions. Yet Johnson shows why this view is overly simplistic. Memories consist of sights, sounds, and other impressions that are distributed all over the brain. Information flows from one neuron to another through tiny neural connections. How memories are stored and solidified depends on changes in connectivity, a nuanced process not bound by well-defined categories.
Johnson’s case raises more questions than it answers. Yet it hints at how much we don’t yet know about memory. It also shows the impact that learning has on the brain and how the interrelationship between body and brain might help us to maintain our abilities over our lifetime.