Autumn is by far my favorite season. I think it’s the way the season pleases my senses — the colors, sounds, and especially smells — that arouse a sense of comfort, safety and nostalgia in me.

Sometimes smells can take me back to a particular event, or even a general sense of contentment. Dead leaves, gasoline, red wine and incense are just a few examples. When I smell certain things, it almost feels like I’m reliving the memories that are aroused.

In Marcel Proust’s novel “Remembrance of Things Past,” he writes, “When nothing else subsists from the past, after the people are dead, after the things are broken and scattered; the smell and taste of things remain poised a long time, like souls; bearing resiliently, on tiny and almost impalpable drops of their essence, the immense edifice of memory.”

So how are smells linked with memories, and therefore, emotions? Originally, smell was used as a mechanism that told us what was safe to eat. As we’ve evolved, our sense of smell has as well.

According to Dr. Karl Kruszelnicki, the Julius Sumner Miller Fellow at Sydney University, humans’ sense of smell, although still five times weaker than that of cats, is acute enough that breast-fed babies can differentiate the smell of their own mothers. Some people can even identify a person’s emotion by the smell of their sweat. Likewise, mammals such as dogs can smell fear in humans.

In the olfactory epithelium, humans have two types of cells used for smell, one of which is called the Bowman’s gland, which produces a thin layer of mucus. Anything we smell must be able to dissolve in this layer of mucus, which then presents the chemical smell to the olfactory neurons. Once a chemical dissolves in the mucus layer, it stimulates millions of receptor cells, which then generate electrical signals.

”These 10 million-or-so receptor cells send their signals to about 50,000 cells in the olfactory bulb, just inside the skull,” Kruszelnicki said. “This has the effect of increasing the sensitivity of our sense of smell. These receptor cells are actually nerve cells.”

Since olfactory receptor nerve cells regenerate themselves roughly every 40 days in the same location of the olfactory bulb, we remember smells. But that still doesn’t explain how memory and emotions are linked with smells.

As the nerves leave the olfactory bulb, they are sent to the thalamus, and, for primates exclusively, the frontal cortex. The frontal cortex allows us to recognize certain smells and sends that message to the limbic system, also referred to as the “emotional brain.” The limbic system includes the amygdala, which processes emotion, as well as the hippocampus, which is involved with associative learning and conditioned responses.

For example, the smell of lavender might remind you of a particular occasion. But smell can also activate the subconscious and influence your mood, so the lavender scent might make you feel happiness.

Even though autumn is an inevitable sign that winter is coming, I associate it with a kind of rebirth or chance to start over.