This article was originally published by Medical News Today. You can find a link to the full article on the bottom of the page. 

When the smell of Madeleines prompted Proust to write hundreds of pages worth of memories, little did he know that he was helping uncover a new area of neuroscientific study.

Decades later, researchers hypothesized that the exceptional ability that smells have to trigger memories — known as "the Proust effect" — is due to how close the olfactory processing system is to the memory hub in the brain.

Indeed, the amygdala, the almond-shaped brain structure that processes sensory information, and the hippocampus, the area responsible for storing episodic memories for later access, sit close together in the brain.

Episodic memories are autobiographical memories of specific past events. In Proust's case, the smell of Madeleines triggered memories about his aunt's "old grey house upon the street, [...] and with the house the town, from morning to night and in all weathers, the square where I used to be sent before lunch, the streets along which I used to run errands, the country roads we took when it was fine."

It's no coincidence that Proust's memories were about space and time. New research shows that spatiotemporal information is integrated in a brain region known as the anterior olfactory nucleus (AON), which is implicated in Alzheimer's disease.