Category: Memory

Why some memories last a lifetime and others are quickly forgotten.

Memories that last a lifetime need to be linked to lots of other memories, plus they need to be a bit weird.

These are the two key components of memories that have the potential to last a lifetime.

Professor Per Sederberg, an expert on memory, thinks the idea of peculiarity is vital to understanding memory:

“You have to build a memory on the scaffolding of what you already know, but then you have to violate the expectations somewhat.

It has to be a little bit weird.”

This ‘scaffolding’ means connections to other memories.

For example, memories of our childhoods are linked to lots of other memories about our families and the places we lived.

And which are the stories we remember best — the ones that stand out?

Of course, it is the ones where something unusual happened: when Grandad told you he was in a band years ago and astonished you by playing the guitar.

It is when you were cycling home and happened to pass your mother in the street wearing a dragon costume and holding a cricket bat.

How memories are stored and retrieved

In one of Professor Sederberg’s studies people wore smartphones around their necks for a month.

These automatically took photos at random intervals.

Later, they relived these memories in the brain scanner so researchers could see where and how the memories were stored and retrieved.

Think of all your memories as being like a vast network, Professor Sederberg said:

“If we want to be able to retrieve a memory later, you want to build a rich web.

It should connect to other memories in multiple ways, so there are many ways for our mind to get back to it.

You want to have a lot of different ways to get to any individual memory.”

Memorable experiences often happen in familiar contexts, but have some peculiar, unpredictable aspect, said Professor Sederberg:

“Those peculiar experiences are the things that stand out, that make a more lasting memory.”

This is why some memories last a lifetime and others are quickly forgotten.

Professor Sederberg was speaking at the Cannes Lions Festival of Creativity in France on June 19. The study referenced was published in the journal PNAS (Nielson et al., 2015).

Working memory is vital to holding pieces of visual, verbal or other information in your mind while you manipulate them.

Even healthy young people can improve their memory by increasing their omega-3 intake, research finds.

The six-month study showed that omega-3 supplements increased people’s working memory.

Professor Bita Moghaddam, a study author, said:

“Before seeing this data, I would have said it was impossible to move young healthy individuals above their cognitive best.

We found that members of this population can enhance their working memory performance even further, despite their already being at the top of their cognitive game.”

Working memory is vital to holding pieces of visual, verbal or other information in your mind while you manipulate them.

Better working memory has been linked to improved learning, attention and other vital outcomes.

Dr Matthew Muldoon, a study co-author, said:

“So many of the previous studies have been done with the elderly or people with medical conditions, leaving this unique population of young adults unaddressed.

But what about our highest-functioning periods?

Can we help the brain achieve its full potential by adapting our healthy behaviors in our young adult life?

We found that we absolutely can.”

The team were also hoping to find the mechanism in the brain that was linked to the improvement in working memory.

Unfortunately brain scans did not reveal evidence of the mechanism they were looking for.

Dr Rajesh Narendarn, the study’s first author, said:

“It is really interesting that diets enriched with Omega-3 fatty acid can enhance cognition in highly functional young individuals.

Nevertheless, it was a bit disappointing that our imaging studies were unable to clarify the mechanisms by which it enhances working memory.”

Participants in the study took a supplement called Lovaza (essentially, fish oil or omega-3) at a dosage of 2g per day.

The supplement had roughly equal amounts of DHA and EPA.

The study was published in the journal PLoS ONE (Narendran et al., 2012).

Each exercise session was only 20-minutes long.

Short bursts of high-intensity exercise provide a considerable boost to memory, research finds.

The study showed that healthy young adults increased their memory performance in a relatively short period of time.

Each exercise session was only 20-minutes long, during which they did short bouts of intense exercise.

Those with the greatest fitness gains saw increases in brain-derived neurotrophic factor (BDNF).

This is a protein that supports the function, growth and survival of brain cells.

Dr Jennifer Heisz, the study’s first author, said:

“Improvements in this type of memory from exercise might help to explain the previously established link between aerobic exercise and better academic performance.

At the other end of our lifespan, as we reach our senior years, we might expect to see even greater benefits in individuals with memory impairment brought on by conditions such as dementia.”

For the study, exercise training was compared with a control group among 95 people.

The high-intensity exercise was particularly beneficial to high-interference memory.

When we try to retrieve something from memory, the retrieval process can be hampered by other similar memories.

For example, when trying to remember someone’s name beginning with the letter ‘J’, the memory might return ‘Jack’, ‘James’ and ‘Jeremy’, before you remember the man’s name is ‘Jeff’.

After exercise, people found it easier to recall memories in these sorts of situations.

Dr Heisz said they were now looking at older adults to see if the same findings held true:

“One hypothesis is that we will see greater benefits for older adults given that this type of memory declines with age.

However, the availability of neurotrophic factors also declines with age and this may mean that we do not get the synergistic effects.”

The study was published in the Journal of Cognitive Neuroscience (Heisz et al., 2017).

Memory can be improved by the right amount of stress, reading, one’s location and even something as simple as saying a word out loud (or not).

In the search for a better memory, scientists have tried all kinds of techniques.

Some of the latest include using laser light to stimulate the prefrontal cortex and optogenetics to control neurons to bring ‘forgotten’ memories back.

In less high-tech realms, the right amount of stress, reading, one’s location and even something as simple as saying a word out loud (or not) have been found to enhance memory.

Still, being forgetful is actually surprisingly common, even among young people, so it is not necessarily a sign of senility.

These ideas and more are explored in these 8 psychology studies on memory from the members-only section of PsyBlog.

(If you are not already, find out how to become a PsyBlog member here.)

1. ‘Forgotten’ Memories Can Be Reawakened By Light
2. Unlocking The Secret To Memorizing New Words
3. These Are The Physical Signs Of A Razor-Sharp Memory
4. Forgetfulness Is Common Even Among Young — Sometimes With Tragic Consequences
5. Painless Laser Therapy Improves Memory By 25% In Minutes
6. How Reading Changes Your Brain
7. The Amount Of Stress That Improves Your Memory
8. Why We Remember More When In New Places

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A study shows that “good” or healthy fats and “bad” fats affect brain cells in different ways.

Diets rich in saturated fat and or refined carbohydrates are linked to neurodegenerative disorders, neuroinflammation, and cognitive dysfunction.

In contrast, diets rich in polyunsaturated fats such as omega-3 and omega-6 fatty acids may have neuroprotective and anti-inflammatory effects.

A study shows that “good” or healthy fats and “bad” fats affect brain cells in different ways.

The research suggests that high-fat diets will reduce polyunsaturated fatty acids and increase saturated fatty acids in the hippocampus.

The hippocampus is part of the brain important for the formation of new memories and learning processes.

The finding may explain the connection between high-fat foods and memory impairment, especially in older people.

Moreover, the study found that omega-3 DHA (docosahexaenoic acid) has the ability to reduce the negative effect of high fat foods-induced inflammation in brain cells.

Previously they showed that eating highly processed foods was linked to higher levels of inflammation in the brain accompanied with memory loss, but DHA supplements averted the issue.

DHA can lower inflammation by acting directly on microglia in response to issues such as traumatic brain injury, neurodegenerative disorders including Alzheimer’s, and brain infections.

Microglia are types of immune cells that are involved in brain development, and inflammatory responses to brain injury.

Dr Ruth Barrientos, the study’s senior author, said:

“The cool thing about this paper is that for the first time, we’re really starting to tease these things apart by cell type.

Our lab and others have often looked at the whole tissue of the hippocampus to observe the brain’s memory-related response to a high-fat diet.

But we’ve been curious about which cell types are more or less affected by these saturated fatty acids, and this is our first foray into determining that.”

DHA protects cells

For this study, microglia cells from animal tissue were taken and developed in the laboratory.

Then these microglia models were exposed to palmitic acid, the most common saturated fat in foods such as shortening, pork, beef, lard, palm oil, and cocoa butter.

The results revealed that palmitic acid caused changes in gene expression involved in the inflammatory response.

However, DHA treatment completely prevented or partially lowered alterations and so protected cells against inflammation.

Dr Michael Butler, the study’s first author, said:

“Previous work has shown that DHA is protective in the brain and that palmitic acid has been detrimental to brain cells, but this is the first time we’ve looked at how DHA can directly protect against the effects of palmitic acid in those microglia, and we see that there is a strong protective effect.

The protective effects of DHA might, in this context, be restricted to effects on gene expression related to the pro-inflammatory response as opposed to the metabolic deficits that the saturated fat also induced.”

Related

• Eating just one meal that is high in saturated fats ruins the ability to concentrate.
• Dry eye syndrome can be an outcome of omega-3 fatty acids deficiency.
• The right balance between omega-3 and omega-6 fatty acids promotes healthy cognitive aging.
• A higher intake of fibre and lower intake of saturated fats can reduce belly fat.
• A mother who eats a high-fat diet can cause life-long changes in the brain of her child.

The study was published in the journal Frontiers in Cellular Neuroscience (Butler et al., 2023).