How Scents Become Long-Lasting Memories

Some scents can trigger memories from many years ago. Neurobiologists Dr Christina Strauch and Professor Denise Manahan-Vaughan from Ruhr University Bochum investigated the area of the brain responsible for storing scents as long-term memories.

Research shows that the piriform cortex — part of the olfactory brain — is involved in consolidating those memories, but only in interaction with other brain areas.

Experiences recreated through stimulation

Synaptic plasticity is responsible for storing memories — it is through changes in communication between neurons that memory is formed. The researchers examined whether the piriform cortex can sustain such a change for more than four hours, which would indicate long-term memory. They mimicked olfactory encoding processes using electrical impulses; the same protocols that consolidate memory in the hippocampus were not sufficient in the piriform cortex, however.

A signal from a higher brain area is required

It turned out that the piriform cortex needs to be "instructed." Only stimulation of the orbitofrontal cortex — responsible for distinguishing sensory experiences — produced a lasting change. The piriform cortex can therefore serve as an archive of long-term memories, but it needs a signal that a given event is to be remembered for a long time.