"If you enter a room in which coffee is brewing, you will quickly look for the coffee machine. The blind person entering the same room will only have the smell of coffee as information," says Mathilde Beaulieu-Lefebvre, a graduate student at the Université de Montréal Department of Psychology. "That smell will therefore become very important for their spatial representation."
Researchers say the findings could lead to concrete applications in the re-adaptation of the blind. Different types of businesses could have distinct scents, for example, which would help blind people get around.
The three-step study tested 25 subjects, 11 of whom were blind from birth. Participants answered a questionnaire and were subjected to two experiments: one where they had to differentiate 16 different perfumes using an olfactometer, another where they lay in a tomodensitometer to identify three smells: a rose, vanilla and butanol (a sweet alcohol).
Using functional imagery, the team determined that the blind use their secondary olfactory cortex more than the sighted when they smell. They also use the occipital cortex, which is normally used for vision. "That's interesting because it means the blind are recuperating that part of their brain," says Maurice Ptito, a professor at the Université de Montréal School of Optometry. "We're not speaking of recycling per se, yet that part of the brain is reorganized and used otherwise."