Aphantasia, this cerebral peculiarity which prevents us from having mental images

Aphantasia, this cerebral peculiarity which prevents us from having mental images

Have you ever heard of aphantasia? This term was coined by Adam Zeman, professor of cognitive and behavioral neurology at the University of Exeter in England, to describe people who are unable to visualize an image mentally. Explanations on this cerebral peculiarity.

Ordinary people are capable, by smelling a particular odor, for example, of recalling a precise memory and having a mental image of it. It is this capacity that so-called aphantasic people are deprived of.

What is aphantasia?

A term coined in 2015 by Adam Zeman, professor of cognitive and behavioral neurology at the University of Exeter in England and honorary researcher at the University of Edinburgh in Scotland, aphantasia characterizes people who are unable to generate a mental image, whether this either during a simple discussion or when recalling a memory.

However, specialists describe it as being left-handed, for example. Indeed, aphantasia is not a pathology or a disability, it is simply a particular brain function. Paradoxically, these people are capable of dreaming. “This is possible, because the processes involved in generating images while awake and generating dream imagery are very different.” explains Adam Zeman.

Around 1% of the world population would be affected by this particularity

The term was therefore invented by Professor Zeman after meeting a patient who developed this particularity after heart surgery. “We then studied his brain scans and found that when he looked at things, his brain responded normally, but when he tried to imagine them, there was no activation of the visual regions of the brain..

Questioned by our colleagues at CNN, Mary Wathen also reports having never had the experience of visualizing a memory. She is unable to see herself as a child, opening her Christmas presents, to remember her husband’s marriage proposal or even the birth of her children.

Aphantasia can be innate or acquired

Since 2015, scientists have further studied aphantasia, in order to better understand its mechanisms. According to Adam Zeman, aphantasia can be associated with memory problems, autism or “face blindness”, the disorder which prevents people from recognizing most faces, even those of loved ones.

People with aphantasia are also more likely to work in science, mathematics or information technology” indicates the researcher. “And although aphantasia can be caused by a brain injury, some people, like Mary Wathen and her mother, inherited it at birth. We’ve found that if you have aphantasia, your first-degree relatives are about 10 times more likely to have it as well.“. Observation which suggests that a genetic origin would be responsible for this particularity.

The opposite of aphantasia, hyperphantasia

Unlike people with aphantasy, there are those who have “too many” mental images. These people are called hyperphantasic. Scientists estimate that this affects 3% of the world’s population.

In hyperphantasia, on the contrary, people are able to relive their memories in detail. The letters and numbers have particular colors and the people are seen surrounded by an aura, more or less vivid. “These people often work in the artistic field and may experience heightened emotions.” adds Adam Zeman. Brain analyzes have also shown that people suffering from hyperphantasia have “fairly strong links between the front of the brain and the sensory centers located at the back” further indicates the neurologist. “Whereas in cases of aphantasia, these connections are much weaker“.

But experiencing memories intensely is not without risks. The specialist fears that with hyperphantasia, patients will be “more prone to post-traumatic stress disorder“, car “they sometimes confuse what they imagined with what really happened or constantly visualize the horrible consequences of an event, even though they did not happen“.