Your Brain on Aromatherapy

Jasmine, rose, and sandalwood; these are the scents that permeate my childhood memories. From the burning of incense sticks to the steady stream of fragrances coming from my essential oil diffuser, this is how I know I’m home – something that you may be familiar with as “aromatherapy”, the use of aromatic materials to enhance psychological and physical well-being.

Aside from serving as a non-toxic way to make your house smell good, aromatherapy can be used as a complementary and alternative medicine practice, which encompasses non-traditional medical therapies such as acupuncture, aromatherapy, or homeopathy. Aromatherapy uses essential oils, which are concentrated aromatic compounds naturally extracted from the oil sacs of anything ranging from flowers and seeds to fruits and rinds. Once these volatile oils are extracted, the two most common methods of usage are through diffusion and massage.

Aromatherapy and the Brain

One of the primary reasons why aromatherapy can affect our brain is due to the unique relationship between our brain and sense of smell. Inhaled essential oil molecules activate neural signaling in the olfactory bulb, the region of the brain that captures and sends out information regarding smell. This stimulus then travels to the limbic system of the brain, a region that regulates emotion and cognition - specifically to the amygdala and hippocampus. These two limbic structures that are responsible for forming emotional responses and memory encoding, respectively. The limbic system then interacts with the cerebral cortex, which activates specific thoughts, feelings, and actions, and the olfactory cortex receives nerve signals that trigger the release of neurotransmitters such as serotonin.

Olfaction and the limbic system are incredibly intertwined; in fact, smell is the only sense that bypasses processing in the thalamus, the region of the brain that processes information gained from all our other senses except smell. Instead, stimuli from scents go straight to the olfactory bulb, which is directly connected to the limbic system, and thus olfactory perception is dominated by an emotional response to the scent. For example, you may be more likely to remember that your dirty socks “smell bad” rather than what exactly they smell like. The close interaction between our brain and scent is what allows smells to strongly trigger certain emotions and memories compared to our other senses, even inducing calming, stress-relieving effects on our minds.