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| English: Main regions of the vertebrate brain, shown for a shark and a human brain (the human brain is sliced along the midline). The two brains are not on the same scale. (Photo credit: Wikipedia) |
In 2005, a 65-year-old retired building inspector paid a visit to the neurologist Adam Zeman at the University of Exeter Medical School in England. After a minor surgical procedure, the man-whom Dr. Zeman and his colleagues refer to as MX-had suddenly realized he could not conjure images in his mind.
Dr. Zeman could not find the condition in medical literature. He was intrigued. For decades, scientists had debated how the mind’s eye works, and how much we rely on it to store memories and to make plans for the future.
MX agreed to a series of exams. He proved to have a good memory for a man of his age, and he performed well on problem-solving tests. His only unusual mental feature was an inability to form mental images.
Dr. Zeman then scanned MX’s brain as he performed certain tasks. First, MX looked at faces of famous people and named them. The scientists found that certain regions of his brain became active, the same ones that become active in other people who look at faces.
Then the scientists showed names to MX and asked him to picture their faces. In normal brains, some of those face-recognition regions again become active. In MX’s brain, none did.
Yet MX could answer questions that would seem to require a working mind’s eye. He could tell the scientists the color of Tony Blair’s eyes, for example, and name the letters of the alphabet that have low-hanging tails, like g and j. These tests suggested his brain used some alternate strategy to solve visual problems.
Since then, scientists have surveyed other people who say they cannot summon mental images-as if their mind’s eye were blind. Many of the survey respondents differed from MX in an important way. While he originally had a mind’s eye, they never did.
Reported in the journal Cortex, the condition has received a name: aphantasia, based on the Greek word phantasia, which Aristotle used to describe the power that presents imagery to our minds.
If aphantasia is real, it is possible that injury causes some cases while others begin at birth.
Thomas Ebeyer, a 25-year-old Canadian student, discovered his condition four years ago while talking with a girlfriend. He was shocked that she could remember what a friend had been wearing a year before. She replied that she could see a picture of it in her mind.
“I had no idea what she was talking about,” he said. He was then surprised to discover that everyone he knew could summon images to their minds.
Like many other survey subjects, he could count his windows without picturing his house.
It’s weird and hard to explain,” he said. “I know the facts. I know where the windows are.”
Dr. Zeman is trying to ascertain how common aphantasia is. He has sent the questionnaire to thousands of people and wants to hear from more. He can be reached at a.zeman@exeter.ac.uk.
Taken from TODAY Saturday Edition, The New York Times International Weekly, July 4, 2015
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