Almost all information about smell is stored in the brain’s hypothalamus, a part of the limbic system, which seems to play an important role in controlling mood, memory, behaviour, emotions, heart rate, blood pressure, respiration, stress, and hormonal balance. When a person inhales a smell, a certain signal is sent to the brain, which then spreads throughout the body. Choosing specific scents can lower our stress levels, boost mood, and improve memory. For better concentration, for example, combine a few drops of rosemary, sweet orange, and basil essential oils in your diffuser to increase your focus and productivity.