Category: Memory

Could memories of drug abuse or trauma be selectively erased?

For some people–those suffering from post-traumatic stress disorder or substance abuse problems–erasing unwanted memories is more than just an idle wish.

With these people in mind, a recent study by scientists at the Scripps Research Institute has managed to selectively erase the memories of mice (Young et al., 2013).

Researchers gave methamphetamine to the mice so that they began to associate the feel-good drug with a particular type of environment filled with novel and interesting tastes, sights and smells.

It’s a bit like how clubbers learn to associate going to a club with taking drugs.

The mice learned that when they were in a particularly exciting context, they should press a lever to get a dose of methamphetamine.

After they’d learnt the habit, the mice were injected with a type of memory inhibitor that affects memories associated with methamphetamine.

Later, when the mice were returned to the exciting environment, they showed little interest in the lever which doled out methamphetamine.

Apparently they’d forgotten the association.

At the same time, tests showed that their other memories were unaffected–the memory inhibitor had selectively erased only the drug-related memories.

One of the researchers, Courtney Miller, explained:

“Not unlike in the movie Eternal Sunshine of the Spotless Mind, we’re looking for strategies to selectively eliminate evidence of past experiences related to drug abuse or a traumatic event. Our study shows we can do just that in mice–wipe out deeply engrained drug-related memories without harming other memories.”

People often think of memory as fragile, but remaining relatively unchanged after it is initially laid down.

This is far from the truth.

In fact memories can be manipulated after the event by changes in the way they are recalled.

For example, if you recall a past embarrassing event over and over again, it will become stronger.

If, instead, you recall a happy moment again, that will become stronger.

Just by recalling (or not recalling) a memory, its relative strength is changing in relation to other memories.

Memories related to powerful drugs, however, are not so easily forgotten, which is why these researchers hope that this type of chemical treatment may eventually be beneficial for those with substance abuse disorders.

→ Continue reading: 8 Ways to Get Rid of Unwanted Negative Thoughts

Image credit: Terrance Heath

New memories can be edited and spliced into old ones, according to a new study.

A new study demonstrates that the way memory works is far from the popular imagination of a video camera; in fact new and old memories are continually being cut-up, edited and spliced together.

The study, conducted by neuroscientists at Northwestern University Feinberg School of Medicine, demonstrates how current memories can be inserted into older ones (Bridge & Voss, 2014).

The lead author of the study, Donna Jo Bridge, used the example of falling in love:

“When you think back to when you met your current partner, you may recall this feeling of love and euphoria. But you may be projecting your current feelings back to the original encounter with this person.”

In the study, participants were shown objects located on the computer screen paired with certain backgrounds.

They were then asked to place the same objects in the same locations on the screen–but there were different backgrounds than they’d seen before.

In a third trial participants had to choose between three locations on the screen, either where they’d appeared the first time, where they’d chosen the second time, or a new location.

Bridge explained the results:

“People always chose the location they picked in part 2. This shows their original memory of the location has changed to reflect the location they recalled on the new background screen. Their memory has updated the information by inserting the new information into the old memory.”

While they were carrying out these tests, participants’ brains were scanned and their eye movements tracked.

The study’s other author, Joel Voss, explained the results:

“Everyone likes to think of memory as this thing that lets us vividly remember our childhoods or what we did last week. But memory is designed to help us make good decisions in the moment and, therefore, memory has to stay up-to-date. The information that is relevant right now can overwrite what was there to begin with.”

Image credit: Scott Kinmartin

It’s a mystery: men report their memory is worse than women.

A new study finds for the first time that men, on average, think they are more forgetful than women.

The results come from a large study of 48,000 people, conducted in Norway (Holmen et al., 2013).

In the study, people were asked nine questions about how good they think their memory is.

The questions asked included:

• Whether they had problems remembering names and dates.
• How good they were at remembering details of conversations.
• If they could remember what they were doing one year ago.

For eight of the nine questions men reported more problems with their memory.

Professor Jostein Holmen, the lead author of the study, explained the results:

“It was surprising to see that men forget more than women. This has not been documented before. It was also surprising to see that men are just as forgetful whether they are 30 or 60 years old. The results were unambiguous.”

The explanation for these findings is beyond them. Holmen said:

“We have speculated a lot about why men report more frequent problems with remembering than women do, but have not been able to find an explanation. This is still an unsolved mystery.”

Across all the categories of questions it was names and dates that people found the hardest to remember.

Naturally the study only looks at people’s perception of how good or bad their memory is–it is not an objective measure.

Still, the importance of looking at subject memory impairment is to see if it might predict cognitive problems in the future, like dementia.

Image credit: Daniela Vladimirova

More than two or three drinks a day damages men’s memory.

A new study has found that men drinking heavily in mid-life experience faster declines in their cognitive abilities.

The study, published in the journal Neurology, found that men who drank the equivalent of 2.5 drinks per day showed faster declines with age (Sabia et al., 2014).

Some people may be surprised just how low the bar is set for ‘heavy’ drinking. What this study calls ‘heavy’ drinking, many would consider ‘moderate’.

Below this level there was little difference in cognitive health between those who abstained and those who had two or less drinks per day.

The study also included women, but there was little evidence of any increased decline in cognitive health from alcohol consumption.

Although moderate drinking is often considered relatively harmless, some recent studies on rats are not so comforting.

A Rutgers University study gave rats the equivalent of five drinks for men and 3-4 for women (Anderson et al., 2012). This is the amount that puts you on the legal driving limit in the US.

The rats’ brains showed a 40% drop in the number of nerve cells in the hippocampus

The study’s lead author, Megan Anderson, explained:

“If this area of your brain was affected every day over many months and years, eventually you might not be able to learn how to get somewhere new or to learn something new about your life. It’s something that you might not even be aware is occurring.”

Image credit: PtM 1985

Caffeine enhances consolidation of long-term memories.

Until now scientists thought that while caffeine has all sorts of effects on the mind, it has little or no influence over long-term memory.

But previous studies generally gave caffeine to people before they began learning.

A new study, published in the journal Nature Neuroscience, gave caffeine to participants after a session of learning.

They found that it boosted a deeper level of long-term memory (Borota et al., 2014).

One of the study’s authors, Michael Yassa, explained that the problem with giving caffeine to people before the learning session is that…

“…if there is an enhancement, it’s not clear if it’s due to caffeine’s effects on attention, vigilance, focus or other factors. By administering caffeine after the experiment, we rule out all of these effects and make sure that if there is an enhancement, it’s due to memory and nothing else,”

One strong cup of coffee

Participants in the study, who were not habitual consumers of caffeine, were given a series of images to view and learn.

Afterwards, some were given a 200mg caffeine tablet (equivalent to one strong cup of coffee), and others were given a placebo.

The next day they were shown a series of images again, except some of them were the same, some different and some similar.

Those who had taken the caffeine pill after learning fared better on the ‘similar’ category of images than those given a placebo pill. Michael Yassa explained the reasoning:

“If we used a standard recognition memory task without these tricky similar items, we would have found no effect of caffeine. However, using these items requires the brain to make a more difficult discrimination — what we call pattern separation, which seems to be the process that is enhanced by caffeine in our case.”

The researchers therefore demonstrated a deeper level of memory encoding resulting from the caffeine than simply recognising or not recognising the images.

The researchers also tried 300mg of caffeine but this had no additional enhancing effect on long-term memory.

→ Read on: What Caffeine Really Does to Your Brain

→ Continue reading: Memory and Recall: 10 Amazing Facts You Should Know

Image credit: Alfred Hermida

Music and memory: it aids language learning, helps injured brains remember, causes widespread brain activation and more…

Music and memory have a tremendously strong link.

Hearing an old song can take you back decades in the blink of an eye.

Psychologists have been fascinated by this connection between music and memory.

Here are five recent psychology studies which demonstrate the intimate link between music and memory.

1. Singing aids language learning

The link between music and memory is so strong that it can help you learn a foreign language.

Research by Ludke et al. (2013) found that people trying to learn Hungarian, a notoriously difficult language, performed much better if they sang the Hungarian phrases rather than just saying them.

The researchers think that the melody may provide an extra cue which helps embed the memory.

2. Music and memory: the injured brain

People who have suffered traumatic brain injuries (TBIs), such as in a car accident, often have problems with memory.

Music is increasingly being tested as a way to help bring back forgotten autobiographical memories.

A recent study had participants who had suffered severe TBIs listening to number-one songs from their lifetimes to see what memories were evoked (Baird & Sampson, 2013).

The memories brought back were mostly of people or a period of their lives and were broadly similar to those evoked by control participants who did not have a TBI.

Compared with using a standardised interview–the Autobiographical Memory Interview–playing number-one hits to people who’d suffered TBIs was more effective in eliciting memories.

3. Widespread brain activation

One of the reasons the link between music and memory is so powerful is that it activates such large areas of the brain.

A recent brain imaging study found that music activated the auditory, motor and limbic (emotional) regions (Alluri et al., 2013).

The study found that whether their participants were listening to the Beatles or Vivaldi, largely the same areas of the brain were active.

The motor areas process the rhythm, the auditory areas process the sound, while the limbic regions are associated with the emotions (Alluri et al., 2013).

4. Music can take you back two generations

Classic hits can easily take you back to your teens and twenties.

Most people have particularly strong memories of this time in their lives–psychologists have called it the ‘reminiscence bump’.

But, perhaps surprisingly, one study has shown that people also have mini reminiscence bumps for the music their parents listened to, and even for their grandparents’ music (Krumhansl & Zupnick, 2013).

The study’s lead author, Carol Lynne Krumhansl, explained:

“Music transmitted from generation to generation shapes autobiographical memories, preferences, and emotional responses, a phenomenon we call cascading ‘reminiscence bumps’.

“These new findings point to the impact of music in childhood and likely reflect the prevalence of music in the home environment.”

Another study has shown that we don’t even need to hear the tune to active the link between music and memory–the words are enough (Cady et al., 2008).

For a whole generation, the words “Ice, ice baby”, and for another generation “…living in the gangsta’s paradise” are enough to take them back in time.

5. A unique musical hallucination

The power of the link between music and memory is sometimes frightening.

A recent study from Frontiers in Neurology reported the case of a woman who, one night, suddenly began to hear music playing in her head, like a sort of internal, unstoppable jukebox (Vitorovic & Biller, 2013). The problem continued for months.

When she hummed the songs to her husband, he recognised some of them, but she herself didn’t know what they were or where they came from.

It seemed the songs were so deeply rooted in her memory that she wasn’t consciously aware she knew them. They only came to the surface during these night-time hallucinations.

She was treated with an anti-seizure medication and her symptoms improved a little.

This is the only known case of this kind of musical hallucination.

→ Continue reading: Memory and Recall: 10 Amazing Facts You Should Know

Image credit: flyzipper

Three-month-long experiment demonstrates the importance of challenging new activities for older minds.

Older people are often advised to keep active for cognitive health, but passive activities like listening to music or doing puzzles may not be enough.

According to a recent study published in Psychological Science, in order to boost cognition, activities need to be active and mentally taxing.

In their study, Park et al. (2013) randomly divided 221 people aged between 60 and 90 into a series of groups:

• One group took up photography or quilting, or both, and engaged in the activity for 15 hours a week over three months.
• One control group took part in social activities like playing games or watching movies, but did not learn any new skills.
• Another control group completed word puzzles or listened to classical music.

After three months those who had been learning photography or quilting showed improved memory function.

In comparison those listening to music, doing puzzles or engaging in social activities had not improved.

This study clearly shows the importance of engaging with taxing activities, especially in later years. The lead author Denise Park explained:

“It seems it is not enough just to get out and do something–it is important to get out and do something that is unfamiliar and mentally challenging, and that provides broad stimulation mentally and socially. When you are inside your comfort zone you may be outside of the enhancement zone.”

This is one of only a handful of studies to experimentally show the benefits keeping an active mind.

Previous studies have been correlational: in other words they have only an association  between staying mentally active and improved cognitive skills.

The problem with these sorts of studies is we don’t know that it’s staying mentally active that is really causing older minds to be sharper. It could be, for example, that people whose minds are sharper are more likely to take on more challenging activities.

However, this study is good evidence that it’s actually the mentally stimulating activities with which people are engaging that really is causing the improvements in memory.

‘Successful’ ageing

It’s also a great study because it includes activities people might actually enjoy!

Who wants to sit, slogging away at brain training apps when you could be doing something fun like photography?

And, of course, it doesn’t have to be photography, it just has to be something which requires your active mental engagement.

You could just as easily see these benefits from learning another language, playing bridge or any other reasonably complex and challenging activity.

It’s interesting to note, though, that in this study learning photography was more beneficial than the quilting, probably because it requires learning so much new information. Quilting, on the other hand, after the initial learning, is mostly a procedural skill.

With the average age in countries around increasing, these types of findings will become more and more important:

“…unlike computer training, productive engagement has the potential to be self-reinforcing and propagate continued learning and intellectual stimulation. […] The present results provide some of the first experimental evidence that learning new things and keeping the mind engaged may be an important key to successful cognitive aging…” (Park et al., 2013)

Image credit: Leo Herbert