Long-Term Memory

The Link Between Smell and Memory

The sense of smell has the highest association with memory of any sense, and it can elicit emotionally rich memories. The sense of smell is notably different from the other senses. The brain processes odors differently. The nerves in the nose have direct connections to the primary olfactory cortex, which has direct connections to the amygdala and hippocampus, which are involved in emotion and memory consolidation, respectively.

The Olfactory Pathway

When an odor is detected, the olfactory neurons in the upper region of the nasal cavity generate an impulse that travels to the brain via the olfactory nerve. The signal first reaches the brain through the olfactory bulb, where it gets processed before the information about the smell moves to the limbic system. That gives the sense of smell the closest linkage with memory and makes it the most emotive sense compared to other senses. Scents, therefore, have a ‘superhighway' to emotion and memory, and none of the remaining senses follows such a neural pathway. The other sensory nerves connect to the hypothalamus. Besides, as opposed to the cells of the other senses, the scent cells get renewed every thirty to sixty days, and they are the only component of the cranial nerve that can undergo regeneration.

The Unique Nature of Smell

Such differences mean that the sense of smell is the only sense among the five primary human senses that does not get filtered by the brain's cortex. All the other senses, including the sense of sight, touch, sound, and taste get filtered by the brain's cortex before individuals can respond or react to them. Therefore, since smell travels directly to the brain without any form of filtration, people are unable to control their reaction to smell.