New Delhi: There are many ways to support brain health, from exercising regularly to learning new skills. But could something as simple as wearing a particular scent also change the structure of the brain?
A study by researchers from Kyoto University and the University of Tsukuba in Japan found that continuous exposure to rose scent was associated with an increase in grey matter volume in certain areas of the brain.
For the study, 28 women were asked to wear rose essential oil on their clothing continuously for one month. Another 22 volunteers served as a control group and used plain water instead. Before and after the experiment, the participants underwent magnetic resonance imaging (MRI) scans to examine changes in their brain structure.
The scans showed that the participants exposed to the rose scent experienced an increase in overall grey matter volume. However, the changes were not the same across all regions of the brain.
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Rewiring the brain with scents
The researchers found little change in the amygdala, a brain region involved in processing emotions, or the orbitofrontal cortex, which is involved in processing pleasant smells. The most significant increase was found in the posterior cingulate cortex, or PCC, a region associated with memory and the formation of associations.
The researchers believe the finding could be linked to the way the brain processes smells and stores memories associated with them.
Previous research has found that people with impaired smell function can show reduced activity in the amygdala but increased activity in the PCC. The researchers suggest that something similar could have happened among the participants exposed continuously to the rose scent.
Because the scent was constantly present, the amygdala may not have needed to repeatedly respond to it. Meanwhile, the PCC may have continued processing the smell and its associated memories.
“The PCC is involved in memory-odor associations, odor memory retrieval, and semantic memory processes,” the researchers wrote.
However, the study does not establish that wearing rose perfume makes people smarter or improves their cognitive abilities. The researchers also could not determine exactly why grey matter volume increased.
One possibility they raised was that the rose scent may have been perceived as unpleasant by the brain. If so, the emotional regulation required to deal with that response could have caused the PCC to work harder, potentially contributing to the structural changes.
The findings could nevertheless have implications for research into aromatherapy, brain plasticity and neurodegenerative diseases. The PCC is known to shrink in people with Alzheimer’s disease, raising the possibility that regularly stimulating the region through smell could have a protective effect.
The researchers suggested that continuous inhalation of rose essential oil could potentially help prevent brain atrophy and dementia, but this remains a hypothesis that requires further investigation.
The study involved only 50 participants and lasted one month, so much larger and longer studies would be needed to determine whether the changes are lasting, whether other scents produce similar effects and whether they have any meaningful impact on cognition or dementia risk.