The Science of Smell 

Our nasal passages have millions of smelling sensors known as cilia. These passages carry odor molecules that attach to the neurons at the base of the nasal passage, where the limbic system – the seat of memory and emotion – receives them.

Known as the olfactory bulb, the smell center of the brain generates smells. Each olfactory receptor can detect only a small number of smells, so there are over 1,000 genes involved in coding for olfactory receptors.

This means that no single receptor can understand every possible smell. Once the signals have been routed to olfactory bulb microregions, different microregions focus on different odors. Those signals are then interpreted by the olfactory bulb into smells. Odors go directly to the limbic system, including the amygdala and the hippocampus, which are the regions linked to emotion and memory.

This Smells Serious! 

Neuroscientists have inferred that this intimate physical connection amidst the regions of the brain associated with memory, emotion, and the sense of smell could explain why our brain associates smells with specific emotional memories. This is plausibly why a lot of smells transport us back to childhood, which is when a lot of smells are experienced for the very first time!

According to a study published in the journal “Cerebral Cortex” by Christina Strauch and Denise Manahan-Vaughan from Ruhr University Bochum in Germany, “The piriform cortex is indeed able to serve as an archive for long-term memories. But it needs instruction from the orbitofrontal cortex — a higher brain area — indicating that an event is to be stored as long-term memory.”

This explains why the smell of aftershave might remind us of our dad or that of new books opens our memories’ floodgates.