Emotional memory is heightened by our senses

You wanted to know

"How do our senses create memories?" asked a young patron at Cook Memorial Library, Libertyville.

The part of the brain that stores emotional memory is the same place that processes sensory information as nerve signals originating from the eyes, ears, mouth, nose and skin land in the brain's sensory cortex.

When emotions and senses are bundled, a sensory memory can be created. That's why warm chocolate chip cookies can bring on a rush of memories with a single whiff - maybe the taste and smell revive a memory of you at a younger age in your kitchen with your mom as she scrapes warm cookies off a baking sheet.

Experts call this experience olfactory-induced nostalgia.

Dr. Alan R. Hirsch, a Chicago-based expert on smell, said most people can recall vivid memories that are combined with a taste or smell sensation.

The olfactory center in the brain, the part that senses smell, is next to the hippocampus, the part that controls memory. Smell is also the oldest sense from an evolutionary standpoint. This function is found within the brain's limbic system, which stores memory.

When an odor molecule enters the nose, thousands of receptors identify the smell and signals are sent to the olfactory bulb. The resulting analysis could be stored in memory or quickly forgotten, depending on the importance or personal meaning of the event.

Smell can be a tool that heightens memory, Hirsch explained.

"Studies have found that when you provide students with a smell or certain candy, like peppermint or butterscotch, when they are learning a word list, they'll have better recall on the exam if they are eating or smelling that same item."

That's called state-dependent learning, Hirsch said. "It enhances and categorizes learning."

Specialists can treat patients with negative emotional barriers by creating new smell memories. Hirsch described soldiers with post-traumatic stress disorder who might experience flashbacks.

"This can be overcome by desensitization, gradually presenting the sense along with a pleasant experience, extinguishing negative experiences and replacing them with positive memories," he said.

Similar results can be achieved for chemotherapy patients, who often have difficulty eating because the chemicals can leave a bad taste in the mouth, decreasing appetite.

"Giving patients a candy after the treatment gives them an aversion to that candy, not to eating. Background sounds also impact how you eat, with rapid beat music enabling people to eat more food," he added.

Sounds and smells can trigger memories for Alzheimer's patients, people who suffer from memory loss. Alzheimer's weakens short-term memory. Studies use music to stimulate cognitive and communication functions in Alzheimer's patients. Music therapy can help these patients become more social.

Check it out

Cook Memorial Library of Libertyville suggests these titles on the senses:

• "Hmm?: The Most Interesting Book You'll Ever Read About Memory" by Diane Swanson

• "Cool Eyewitness Encounters: How's Your Memory?" by Esther Beck

• "I Before E (Except After C): Easy, Cool Ways to Remember Facts" by Susan Randol

• "Wilfrid Gordon McDonald Partridge" by Mem Fox

• "Chester Raccoon and the Acorn Full of Memories" by Audrey Penn

• "My Senses Help Me" by Bobbie Kalman

• "What Happens When You Use Your Senses" By Jacqui Bailey

• "You Can't Smell a Flower with Your Ear: All About Your 5 Senses" by Joanna Cole

• "The Girl Who Heard Colors" by Marie Harris