Can you distinguish the taste of pinot noir versus a rosé? Would you rather listen to jazz or hard rock? Do you prefer to run or lift weights for exercise? Do you like dogs or cats? Do you want to grow flowers or vegetables? To answer any of these questions, you need to use your semantic memory.

Your semantic memory is your store of factual knowledge of the world and the meaning of words. It’s how you know that a pen is for writing and a sunflower is yellow. It’s both the source of your vocabulary and how you know what something is, even if you don’t know, the name of it — like difficulty getting out of bed in the morning is called Dysania. Illegible handwriting, like yours truly, is called griffonage. Kummerspeck is the excess weight you gain from emotional eating. No sweat, I didn’t know these either!

USE EPISODIC MEMORY TO INCREASE YOUR SEMANTIC MEMORY.

Episodic memories are what most people think of as memory. They include information about recent or past events and experiences, such as where you parked your car this morning or the dinner you had with a friend last month. You need to use your episodic memory to learn new information, to form new semantic memory. For a week, month, or year, you might remember where you were and what you were doing when you learned a new fact. Over time, however, you will forget the context and recognize the fact. Once only the fact remains, it is part of your semantic memory.

YOUR BRAIN’S DICTIONARY-THE LEFT TEMPORAL LOBE. 

Research has shown that semantic memory is stored in the left temporal lobe. Several landmark papers have examined where semantic memory is stored in the brain. In 1996, two related studies were published in an article in Nature. For the first, the researchers enrolled over 100 patients who suffered from stroke or other brain lesions in their left temporal lobe. (Put your finger on your left temple, just behind your eye — that’s where the left temporal lobe is located.) They asked these patients to name famous people, animals, and tools that were human-made objects. They found that the location of brain lesions affected recall. Patients with the most anterior lesions (close to their eyes) had the most significant difficulty naming persons. Patients with the most posterior lesions (toward the back of the head) had the greatest problem naming tools. And those with lesions in between these areas had the most difficulty naming animals.

In the second study, the researchers had healthy adults name famous people, animals, and tools while undergoing a positron emission tomography (PET) scan that showed brain activity. As expected, naming people yielded the most anterior activity, tools the most posterior activity, and for animals, the activity was in between.

DEMENTIA MAY ERASE FROM THE DICTIONARY.

More recent research links deterioration of the anterior temporal lobe to the difficulties understanding what a word means exhibited by people with some types of dementia. Although people with Alzheimer's disease most commonly show this abnormality, it is most prominent in a type of aphasia [loss of ability to understand or express speech] known as semantic dementia. When you speak with these individuals, they may start off sounding normal, but you will notice that they refer to all sorts of different items as the ‘thing’ or a similar word. As you talk with them further, you will discover that they do not know what specific terms mean, such as ‘medicine’ or ‘shoe’ — two examples from one of my patients. Someone may forget the word hippopotamus when shown a picture and lose all the knowledge they once had about this (e.g., it is an African animal that lives in rivers). However, unlike Alzheimer's disease, memory for day-to-day events may be adequate. People may also have difficulty recognizing what things are. At later stages, personality is often affected.

SEMANTIC MEMORY IN OTHER BRAIN REGIONS.

Just as our knowledge is not limited to words, neither is our semantic memory limited to the left temporal lobe. The right temporal lobe has been linked to knowledge of nonverbal information (such as a golf ball's weight versus a ping-pong ball) and facial recognition. Other parts of the brain also participate in semantic memory. For example, Frank Sinatra singing ‘Fly Me to the Moon’ sounds like it is stored in your auditory association cortex in your superior temporal lobe. Your image of a brilliant white Tesla is stored in your visual association cortex in your occipital lobes. And the feeling of tulip petals resting on your cheek is stored in your sensory association cortex in your parietal lobe.

SEMANTIC MEMORY DOES NOT DECLINE IN AGING.

Can improving your semantic memory help you do a crossword puzzle? Absolutely. Not only does semantic memory store the meaning of words and nonverbal concepts, but it also stores the relationships within and between terms and concepts.

For example, your semantic memory of the band Pink Floyd may be linked to the President of the United States in the following way: Pink Floyd's album Dark Side of the Moon may be connected in your semantic memory to moon landings, which is then connected to astronauts, to John Glenn, to senators, to politicians, and to presidents.

BOTTOMLINE

Semantic memory does not decline in normal aging. As you continue to learn new information throughout your life, your vocabulary and ability to solve crossword puzzles may improve with age. Scheduling regular periods of rest without distraction could help us all hold onto new material a little more firmly. In the age of information overload, it's worth remembering that our smartphones aren't the only thing that needs a regular recharge. Our minds do too.

References

https://pubmed.ncbi.nlm.nih.gov/27383595/

https://www.sciencedirect.com/science/article/abs/pii/S0010945219300218

Published 11/2/2020

About Us

Dr. Amar Singh, MD, and Dr. Poonam Singh, MD, are board-certified by the American Board of Internal Medicine and American Board of Obesity Medicine. They specialize in preventing, treating, and reversing chronic diseases using an evidence-based holistic approach. They are specifically interested in weight management, hormone re-balancing, and longevity. The American College of Physicians has recognized them as Fellows, FACP,  for their excellence and contributions made to both medicine and the broader community. They enjoy teaching, volunteering, and advocating for their patients. Their mission is to share simple, effective, and proven strategies that lead to meaningful, sustainable, and long-lasting well-being.