Complementary Alternative Cardiovascular Medicine

242 Alternative Cardiovascular Medicine
cerebral cortex, arranged into 53 regions and 35 associated tracts. The
limbic system also receives most sensory input and passes it on to the
voluntary and involuntary motor centers. Gatti and Cayola (9) noted that
odors produced an immediate effect on respiration, pulse, and blood
pressure and, therefore, concluded that odors had, by a reflex action,
produced a dramatic effect on the functioning of the central nervous
system (CNS). Nearly 80 yr later, Singewald et al. (10) found that the
locus coeruleus (situated in the limbic system) played a vital role in
conditioned fear and inescapable shock.
The amygdala and the hippocampus, parts of the limbic system, are
particularly important in aroma processing. The amygdala is believed to
play a pivotal role in processing emotion, particularly the control of
aggression, and in the formation of emotional memory. The amygdala
also governs emotional response and affects survival behavior, because
it is intimately responsible with a sensation of fear. Diazepam (valium)
is believed to reduce the effect of external emotional stimuli by increasing
gamma aminobutyric acid (GABA)-containing inhibitory neurons in
the amygdala. Lavandula angustifolia (true lavender) has a similar effect on
the amygdala, producing a sedative effect that is similar to diazepam (11).
The hippocampus is where molecules in an aroma trigger learned
memory and is involved in the formation and retrieval of explicit memories
(12). The hippocampus is believed to be the storage area for new
experiences before they become permanent memories that are then
thought to be stored in the cerebral cortex.
Smell is important to quality of life, beginning with a newborn baby’s
identification of its mother and continuing into old age, where studies
have shown that the depression of residential elderly was reduced with
fruit and flower aromas.
The effect of odors on the brain has been mapped using computergenerated
topographics. Brain electrical activity maps (BEAM) indicate
how subjects, who are linked to an electroencephalogram (EEG), psychometrically
rated the odors presented to them. Smells can have a psychological
effect even when the aroma is below the level of human
awareness. Provided the olfactory nerve is intact, aromas will affect the
brain even if the subject is anosmic.
CONTEMPORARY USE
Essential oils can be absorbed into the bodies through olfaction, applied
topically or taken internally (13). The components within an essential oil
find their way into the bloodstream regardless of application method
(13). Inhaled aromas have the fastest effect, although components such