Tag: memory

Prompts During Sleep Boosts Recall of Names and Faces

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Hearing names repeated during deep sleep may help bolster recall of names and faces, according to new research from Northwestern University.

The researchers found that people’s name recall improved significantly when memories of newly learned face-name associations were reactivated while they were napping. Uninterrupted deep sleep was key in this improvement.

“It’s a new and exciting finding about sleep, because it tells us that the way information is reactivated during sleep to improve memory storage is linked with high-quality sleep,” said lead author Nathan Whitmore, a PhD candidate in the Interdepartmental Neuroscience Program at Northwestern University.

The research is reported in the Nature partner journal npj Science of Learning.

The three main stages of the experiment of Whitmore et al. (2022). First, participants learned 80 face-name associations. Next, they slept while EEG was monitored to determine sleep stage, and 20 of the spoken names were presented softly over background music during slow-wave sleep. Finally, memory testing showed superior memory due to memory reactivation during sleep, but only when sleep was undisturbed by sound presentations. Credit: Nathan Whitmore, a Ph.D. candidate in the Interdepartmental Neuroscience Program at Northwestern University.

The results also highlighted the importance of adequate sleep: for study participants with EEG measurements that indicated disrupted sleep, the memory reactivation had no effect and may even be detrimental. But in those with uninterrupted sleep during the specific times of sound presentations, the reactivation helped participants recall just over 1.5 more names.

The study recruited 24 participants, aged 18-31 years old, who were asked to memorise the faces and names of 40 pupils from a hypothetical Latin American history class and another 40 from a Japanese history class. When each face was presented again, they were asked to recall the associated name. After the learning exercise, participants took a nap while the researchers carefully monitored brain activity using EEG measurements. When participants reached the N3 “deep sleep” state, some of the names were softly played on a speaker with music that was associated with one of the classes.

When participants awoke, they were again tested on recognising faces and recalling their names.

According to the researchers, the finding on the relationship between sleep disruption and memory accuracy is noteworthy for several reasons.

“We already know that some sleep disorders like apnoea can impair memory,” said Whitmore. “Our research suggests a potential explanation for this—frequent sleep interruptions at night might be degrading memory.”

The lab is currently exploring the reactivation of memories and deliberately disrupting sleep in order to learn more about the relevant brain mechanisms.

Source: EurekAlert!

Earliest Childhood Memories Date Back to Two and a Half

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People’s earliest childhood memories they can recall are on average from just two-and-a-half years old, according to a new study published in the journal Memory.

It was previously held that the earliest memories are from three-and-a-half years old. Research on earliest memories dates back to the late 1800s, when it was first noted that most adults lack memories from the first 3 to 4 years of their lives, a phenomenon later termed infantile or childhood amnesia.

The evidence for the lower age of earliest memories is presented in a new 21-year study, which followed on from a review of already-existing data.

“When one’s earliest memory occurs, it is a moving target rather than being a single static memory,” explained lead author Dr Carole Peterson, a childhood amnesia expert from Memorial University of Newfoundland.

“Thus, what many people provide when asked for their earliest memory is not a boundary or watershed beginning, before which there are no memories. Rather, there seems to be a pool of potential memories from which both adults and children sample.

“And, we believe people remember a lot from age two that they don’t realise they do.

“That’s for two reasons. First, it’s very easy to get people to remember earlier memories simply by asking them what their earliest memory is, and then asking them for a few more. Then they start recalling even earlier memories – sometimes up to a full year earlier. It’s like priming a pump; once you get them started its self-prompting.

“Secondly, we’ve documented those early memories are systematically misdated. Over and over again we find people think they were older than they actually were in their early memories.”

Dr Peterson has conducted studies on memory for over two decades, focusing on the ability of children and adults to recall their earliest years.

This latest study reviewed 10 of her research articles on childhood amnesia followed by analyses of both published and unpublished data collected in Dr Peterson’s laboratory since 1999. This comprised 992 participants, and memories of 697 participants were then compared to the recollections of their parents.

The finding shows that children’s earliest memories date from before when they think it happened, backed up by their parents.

‘Telescoping’ memories

The evidence from this research to move our potential memory clock is “compelling”. For example, when reviewing a study which interviewed children after two and eight years had passed since their earliest memory they were able to recall the same memory, however in the subsequent interviews reported a later age as to when they occurred.

“Eight years later many believed they were a full year older. So, the children, as they age, keep moving how old they thought they were at the time of those early memories,” explained Dr Peterson, from the Department of Psychology at Memorial University.

The finding is due to something in memory dating called ‘telescoping’, she believes.

“When you look at things that happened long ago, it’s like looking through a lens.

“The more remote a memory is, the telescoping effect makes you see it as closer. It turns out they move their earliest memory forward a year to about three and a half years of age. But we found that when the child or adult is remembering events from age four and up, this doesn’t happen.”

She says, after combing through all of the data, it clearly shows that people recall much more of their early childhood, a lot farther back, than they think they do, and helping to access those memories is fairly simple.

“When you look at one study, sometimes things don’t become clear, but when you start putting together study after study and they all come up with the same conclusions, it becomes pretty convincing.”

This lack of clarity is a limitation of her research, she acknowledges, one which is also common to all research done to-date in the subject area.

“What is needed now in childhood amnesia research are independently confirmed or documented external dates against which personally derived dates can be compared, as this would prevent telescoping errors and potential dating errors by parents,” Dr Peterson said.

She is currently doing research on this with verified dating, both in her laboratory and elsewhere to further confirm the answer to this long-debated question.

Source: Taylor & Francis Group

Journal information: Peterson, C., (2021) What is your earliest memory? It depends. Memory. doi.org/10.1080/09658211.2021.1918174.

Scientists Crack Neuron Information Storage Code

A team of scientists from the UK and Australia have discovered that single neurons can store electrical patterns, similar to memories. This represents a breakthrough towards solving how neural systems are able to process and store information.

By comparing predictions from mathematical modeling to lab-based experiments with mammalian neurons, they were able to determine how different parameters, such as how long it takes for neuronal signals to be processed and how sensitive a cell is to external signals, affect how neural systems encode information.

The research team found that a single neuron is able to select between different patterns, dependent on the properties of each individual stimulus, for example slight differences in stimulation timing resulted in the emergence of no electrical activity spikes, single spikes per delay or two spikes per delay,

By opening up new avenues into research on the encoding of information in the brain and how this relates to memory formation, the study could also allow new insights into the causes and treatments of mental health conditions such as dementia.

“This work highlights how mathematical analysis and wet-lab experiments can be closely integrated to shed new light on fundamental problems in neuroscience,” said Dr Wedgwood. “That the theoretical predictions were so readily confirmed in experiments gives us great confidence in the mathematical approach as a tool for understanding how individual cells store patterns of activity. In the long run, we hope that this is the first step to a better understanding of memory formation in neural networks.”

Professor Krauskopf from the University of Auckland remarked, “The research shows that a living neuron coupled to itself is able to sustain different patterns in response to a stimulus. This is an exciting first step towards understanding how groups of neurons are able to respond to external stimuli in a precise temporal manner.”

“Communication between neurons occurs over large distances. The communication delay associated with this plays an important role in shaping the overall response of a network. This insight is crucial to how neural systems encode memories, which is one of the most fundamental questions in neuroscience,” added Professor Tsaneva from the University of Exeter’s Living Systems Institute.

Source: Medical Xpress

Journal information: Kyle C. A. Wedgwood et al, Robust spike timing in an excitable cell with delayed feedback, Journal of The Royal Society Interface (2021). dx.doi.org/10.1098/rsif.2021.0029

Shared Neural System May Be Used for Different Memory Stores

The brain may have a shared neural system that is involved in the retrieval of facts and personal memories used in everyday life, new research has found.

Factual memory had long been categorised into two stores; factual memory and memory of personal experiences. These two repositories in concert enable people to make sense of the world around them. Individuals with retrograde amnesia can fail to remember personal experiences, but still recall factual knowledge. These two stores have been shown by decades of clinical and experimental research to be stored across two separate regions of the brain.

But the new study suggests that a shared set of brain regions play an important role in controlling the successful retrieval of weak memories.

When participants were asked to retrieve fact memories and personal memories, researchers used functional MRI imaging to study how these regions changed in activity levels.

Lead researcher Dr Deniz Vatansever, formerly of the University of York and now working for the Institute of Science and Technology for Brain-inspired Intelligence, Fudan University said: “The new research suggests that despite their functional differences, successfully retrieving weak information from these two memory systems might be dependent upon a shared brain mechanism.

“Our memories allow us to make sense and flexibly interact with the world around us. Although in most cases, our strongly encoded memories might be sufficient for the task at hand, remembering to pack a beach towel for an upcoming seaside holiday, this strong memory may be irrelevant in other instances, such as when packing for a business trip. As such, we need to tightly control the retrieval of relevant memories to solve different tasks under different circumstances. Our results indicate that this control process might be shared across both factual and personal memory types.”

The researchers said their findings may be applicable to memory disorders, including dementia, where patients’ quality of life is affected by being unable to remember important information. The findings could also be relevant in the development of a new generation of AI, which use long-term memory in solving computational problems. 

“In order to generate appropriate thoughts and behaviors, we have to draw on our memory stores in a highly flexible way,” said senior author Elizabeth Jefferies, and professor, Department of Psychology, University of York. “This new study highlights control processes within the brain that allow us to focus on unusual aspects of the meanings of words and to retrieve weakly encoded personal experiences. This control over memory allows us to be creative and to adapt as our goals or circumstances change.”

Source: News-Medical.Net

Journal information: Vatansever, D., et al. (2021) Varying demands for cognitive control reveals shared neural processes supporting semantic and episodic memory retrieval. Nature Communications. doi.org/10.1038/s41467-021-22443-2.