Front Matter

Olfaction and Autism 85

for both olfactory and gustatory (sense of taste) diagnostic assessment. Specific
olfactory environments that are favorable to ASD patients could potentially
enhance the quality of their neurophysiological wellbeing. For example,
olfaction has reinforcement potential. Those with ASD tend to be more
effective with sorting tasks when a more pleasant smell, such as that of an
orange, is present. One must be careful not to impose what is pleasant to
those without ASD on those who are affected. For example, an experimental
group of boys with either high functioning autism or Asperger syndrome,
assessed via a test known as Sniffin’ Sticks, found the smell of cloves, pineap-
ple, and cinnamon far less pleasant than did the control group of typical
individuals [15]. Brain networks as they relate to olfactory ability involve
carefully orchestrated coordination between central areas (important in odor
identification tasks) and peripheral ones (important in sensitivity tasks).
Since the same areas, especially the orbitofrontal cortex, are involved in ASD,
olfactory research can inform ASD research, and vice versa. The orbitofron-
tal cortex is vital to higher level olfactory function and is crucial to flexible
behavior and social control. Similarly, the improper functioning of the amyg-
dala is strongly related to both ASD characteristics and loss of olfactory and
gustatory capacity (Figure 3.1).

Tr act

Thalamus Amygdala

Hippocampus

Raphe nucleus

Locus ceruleus

Pituitary gland

Hypothalamus

Olfactory bulb

Odor/smell

stimulation

signaling

Olfactory
epithelium

Figure 3.1 Neural pathways of olfaction. Source: https://www.google.com/search?
newwindow=1&hl=en&site=imghp&tbm=isch&source=hp&biw=1264&bih=576&q=
OLFACTORY‐Sketch&oq=OLFACTORY‐Sketch&gs_l=img.3...1518.3940.0.5304.3.3.0.0.0.0.45.8
7.2.2.0....0...1.1.64.img..1.0.0.0.kQrt2CdsE_4#imgrc=uyYvJhZrR‐7EhM. Adapted from
diy‐stress‐relief.com. (See insert for color representation of this figure.)