A new study published in the scientific journal Cerebral Cortex found that your brain actually plays a pivotal role in the relationship between odours and long-term memories.
How do nostalgic scents transport you back in time? What is the brain mechanism that can turn a certain scent into a full blown long-term memory? A team of neuroscientists from the Ruhr-Universitaet-Bochum university investigate why odours have the ability to trigger memories. The study, led by Dr. Christina Strauch and Dr. Denise Manahan-Vaughan, was published in the journal Cerebral Cortex just before Christmas – a time of the year famous in most Western countries for its highly recognisable smell.
In their study on Wistar rats, whose brains are extremely similar to those of humans, the German researchers focused on the piriform cortex, an area of the brain in the olfactory system responsible for encoding and temporarily storing information for retrieval. It is located near the brainstem at the base of the skull. “It is known that the piriform cortex is able to temporarily store olfactory memories. We wanted to know if that applies to long-term memories as well,” said Strauch.
When storing memories, communication between neurons are altered during a process known as synaptic plasticity, thus creating a memory. By sending electrical impulses through the rats’ brains, Strauch and Manahan-Vaughan were trying to assess if their piriform cortices were capable of storing memories for more than four hours, which would imply synaptic plasticity.
It turns out that the piriform cortex is indeed able to serve as an archive for long-term memories, but it needs instruction from a higher brain area associated with sensory experiences: the orbitofrontal cortex. For the first time, researchers have pinpointed the pivotal role that regions of the brain situated in the frontal lobes play in the encoding of long-term olfactory memories. It was found that the piriform cortex is indeed associated with the process of storing these memories, but that it only works in interaction with other areas of the brain.
As the authors state in their conclusion: “This finding also suggests that top-down control of olfactory information processing is a major determinant of long-term information storage in the piriform cortex and that the piriform cortex may serve as a repository of memories with regard to odour discrimination and categorization.”
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