Lemons and their nutritional and nutraceutical properties are the subject of many research studies, and their benefits are becoming well known. But, the whole field of research into scents and how they affect us is only beginning to scratch the surface.
From nose to brain: The effect of lemon inhalation observed by whole brain voxel to voxel functional connectivity is a paper that was recently published by Belgian and French researchers in the journal Cortex.
What We Know
Several previous studies have looked at the effects of scents such as lemon or lavender. The scent of lemons is known to have certain stimulating properties. It’s the how that is still not largely a mystery. Here’s what is known about the connection so far.
- The neurons responsible for scent can connect directly with the brain networks;
- The olfactory bulb, a gathering of tissues and nerves located roughly at the top of the nasal cavity, is the first area where scents are registered in the body;
- The olfactory bulb projects that information to various regions of the brain associated with higher functions.
Just how the chemical input of scent triggers emotions, though, isn’t well understood at all.
The study used 21 healthy young men at a university, and looked at the effect of inhaling lemon essential oil specifically on their alertness levels. MRI (magnetic resonance imaging) was used to observe nerve activity. Three types of exposure were used in the study:
- A resting state;
- Passive smelling (alternating lemon and fresh air);
- A control condition with no lemon fragrance.
Levels of alertness were measured using standard and broadly accepted testing protocols.
- After lemon fragrance, higher levels of alertness as compared to the resting state;
- As they inhaled the fragrance, there was increased activity in the thalamus, and decreased activity in some cortical regions of the brain.
The regions of the brain that were affected are known to be involved with processing the sense of smell, as well as the emotions. The thalamus, in particular, seems to represent a major gateway that transfers scent information to the cortex of the brain.
As the researchers point out, while certainty is still lacking, the interest in scent research and how it can influence human behavior is growing, including commercial applications. More studies are needed to delve into this fascinating area of research.
- Check out our DIY recipe for making your own lemon essential oil here to enjoy anytime.