Posts Tagged ‘memory’

what-is-your-first-memory-and-did-it-ever-really-happen-309444

By Dr. Lucy Justice

I can remember being a baby. I recall being in a vast room inside a doctor’s surgery. I was passed to a nurse and then placed in cold metal scales to be weighed. I was always aware that this memory was unusual because it was from so early in my life, but I thought that perhaps I just had a really good memory, or that perhaps other people could remember being so young, too.

What is the earliest event that you can remember? How old do you think you are in this memory? How do you experience the memory? Is it vivid or vague? Positive or negative? Are you re-experiencing the memory as it originally happened, through your own eyes, or are you watching yourself “acting” in the memory?

In our recent study, we asked more than 6,000 people of all ages to do the same, to tell us what their first autobiographical memory was, how old they were when the event happened, to rate how emotional and vivid it was and to report what perspective the memory was “seen” from. We found that on average people reported their first memory occurring during the first half of the third year of their lives (3.24 years to be precise). This matches well with other studies that have investigated the age of early memories.

What does this mean for my memory of being a baby then? Perhaps I do just have a really good memory and can remember those early months of life. Indeed, in our study, we found that around 40% of participants reported remembering events from the age of two or below – and 14% of people recalled memories from age one and below. However, psychological research suggests that memories occurring below the age of three are highly unusual – and indeed, highly improbable.

The origin of memory

Researchers who have investigated memory development suggest that the neurological processes needed to form autobiographical memories are not fully developed until between the ages of three and four years. Other research has suggested that memories are linked to language development. Language allows children to share and discuss the past with others, enabling memories to be organised in a personal autobiography.

So how can I remember being a baby? And why did 2,487 people from our study remember events that they dated from the age of two years and younger?

One explanation is that people simply gave incorrect estimates of their age in the memory. After all, unless confirmatory evidence is present, guesswork is all we have when it comes to dating memories from across our lives, including the very earliest.

But if incorrect dating explained the presence of these memories, we would expect that they would be about similar events to those memories from ages three and above. But this was not the case – we found that very early reported memories were of events and objects from infancy (pram, cot, learning to walk) whereas older memories were of things typical of childhood (toys, school, holidays). This finding meant that these two groups of memories were qualitatively different and ruled out the misdating explanation.

If research tells us that these very early memories are highly unlikely, and we have ruled out a misdating explanation, then why do people, including me, have them?

Pure fiction?

We concluded that these memories are likely to be fictional – that is, that they never in fact occurred. Perhaps, rather than recalling an experienced event, we recall imagery derived from photographs, home movies, shared family stories or events and activities that frequently happen in infancy. These facts are then, we suggest, linked with some fragmentary visual imagery and are combined together to form the basis of these fictitious early memories. Over time, this combination of imagery and fact begins to be experienced as a memory.

Although 40% of participants in our study retrieved these fictitious memories, they are not altogether surprising. Contemporary theories of memory highlight the constructive nature of memory; memories are not “records” of events, but rather psychological representations of the self in the past.

In other words, all of our memories contain some degree of fiction – indeed, this is the sign of a healthy memory system in action. But perhaps, for reasons not yet known, we have a psychological need to fictionalise memories from times of our lives that we are unable to remember. For now, these “stories” remain a mystery.

https://theconversation.com/what-is-your-first-memory-and-did-it-ever-really-happen-95953

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We may go to sleep at night, but our brains don’t. Instead, they spend those quiet hours tidying up, and one of their chores is to lug memories into long-term storage boxes.

Now, a group of scientists may have found a way to give that memory-storing process a boost, by delivering precisely timed electric zaps to the brain at the exact right moments of sleep. These zaps, the researchers found, can improve memory.

And to make matters even more interesting, the team of researchers was funded by the Defense Advanced Research Projects Agency (DARPA), the U.S. agency tasked with developing technology for the military. They reported their findings July 23 in The Journal of Neuroscience.

DARPA Wants to Zap Your Brain to Boost Your Memory
Credit: Shutterstock
We may go to sleep at night, but our brains don’t. Instead, they spend those quiet hours tidying up, and one of their chores is to lug memories into long-term storage boxes.

Now, a group of scientists may have found a way to give that memory-storing process a boost, by delivering precisely timed electric zaps to the brain at the exact right moments of sleep. These zaps, the researchers found, can improve memory.

And to make matters even more interesting, the team of researchers was funded by the Defense Advanced Research Projects Agency (DARPA), the U.S. agency tasked with developing technology for the military. They reported their findings July 23 in The Journal of Neuroscience.

If the findings are confirmed with additional research, the brain zaps could one day be used to help students study for a big exam, assist people at work or even treat patients with memory impairments, including those who experienced a traumatic brain injury in the military, said senior study author Praveen Pilly, a senior scientist at HRL Laboratories, a research facility focused on advancing technology.

The study involved 16 healthy adults from the Albuquerque, New Mexico, area. The first night, no experiments were run; instead, it was simply an opportunity for the participants to get accustomed to spending the night in the sleep lab while wearing the lumpy stimulation cap designed to deliver the tiny zaps to their brains. Indeed, when the researchers started the experiment, “our biggest worry [was] whether our subjects [could] sleep with all those wires,” Pilly told Live Science.

The next night, the experiment began: Before the participants fell asleep, they were shown war-like scenes and were asked to spot the location of certain targets, such as hidden bombs or snipers.

Then, the participants went to sleep, wearing the stimulation cap that not only delivered zaps but also measured brain activity using a device called an electroencephalogram (EEG). On the first night of the experiment, half of the participants received brain zaps, and half did not.

Using measurements from the EEG, the researchers aimed their electric zaps at a specific type of brain activity called “slow-wave oscillations.” These oscillations — which can be thought of as bursts of neuron activity that come and go with regularity — are known to be important for memory consolidation. They take place during two sleep stages: stage 2 (still a “light” sleep, when the heart rate slows down and body temperature drops) and stage 3 (deep sleep).

So, shortly after the participants in the zapping group fell into slow-wave oscillations, the stimulation cap would deliver slight zaps to the brain, in tune with the oscillations. The next morning, all of the participants were shown similar war-zone scenes, and the researchers measured how well they detected targets.

Five days later, the groups were switched for the second night of experiments.

The researchers found that, the mornings after, the participants who received the brain zaps weren’t any better at detecting targets in the same scene they saw the night before, compared with those who slept without zaps. But those who received the zapping were much better at detecting the same targets in novel scenes. For example, if the original scene showed a target under a rock, the “novel” scene might show the same target-rock image, but from a different angle, according to a press release from HRL Laboratories.

Researchers call this “generalization.” Pilly explained it as follows: “If you’re [studying] for a test, you learn a fact, and then, when you’re tested the following morning on the same fact … our intervention may not help you. On the other hand, if you’re tested on some questions related to that fact [but] which require you to generalize or integrate previous information,” the intervention would help you perform better.

This is because people rarely recall events exactly as they happen, Pilly said, referring to what’s known as episodic memory. Rather, people generalize what they learn and access that knowledge when faced with various situations. (For example, we know to stay away from a snake in the city, even if the first time we saw it, it was in the countryside.)

Previous studies have also investigated the effects of brain stimulation on memory. But although they delivered the zaps during the same sleep stage as the new study, the researchers in the previous studies didn’t attempt to match the zaps with the natural oscillations of the brain, Pilly said.

Jan Born, a professor of behavioral neuroscience at the University of Tübingen in Germany who was not part of the study, said the new research showed that, “at least in terms of behavior, [such a] procedure is effective.”

The approaches examined in the study have “huge potential, but we are still in the beginning [of this type of research], so we have to be cautious,” Born told Live Science.

One potential problem is that the stimulation typically hits the whole surface of the brain, Born said. Because the brain is wrinkled, and some neurons hide deep in the folds and others sit atop ridges, the stimulations aren’t very effective at targeting all of the neurons necessary, he said. This may make it difficult to reproduce the results every time, he added.

Pilly said that because the zaps aren’t specialized, they could also, in theory, lead to side effects. But he thinks, if anything, the side effect might simply be better-quality sleep.

https://www.livescience.com/63329-darpa-brain-zapping-memory.html

By Timothy Roberts

Being able to recall memories, whether short-term or long-term is something that we all need in life. It comes in handy when we are studying at school or when we are trying to remember where we left our keys. We also tend to use our memory at work and remembering somebody’s name is certainly a good thing.

Although many of us may consider ourselves to have a good memory, we are all going to forget things from time to time. When it happens, we might feel as if we are slipping but there may be more behind it than you realize.

Imagine this scenario; you go to the grocery store to pick up 3 items and suddenly, you forget why you were there. Even worse, you may walk from one room to another and forget why you got up in the first place!

If you often struggle with these types of problems, you will be happy to learn that there is probably nothing wrong with you. In fact, a study that was done by the Neuron Journal and it has some rather good news. It says that forgetting is part of the brain process that might actually make you smarter by the time the day is over.

Professors took part in a study at the University of Toronto and they discovered that the perfect memory actually doesn’t necessarily reflect your level of intelligence.

You might even be surprised to learn that when you forget details on occasion, it can make you smarter.

Most people would go by the general thought that remembering more means that you are smarter.

According to the study, however, when you forget a detail on occasion, it’s perfectly normal. It has to do with remembering the big picture compared to remembering little details. Remembering the big picture is better for the brain and for our safety.

Our brains are perhaps more of a computer than many of us think. The hippocampus, which is the part of the brain where memories are stored, tends to filter out the unnecessary details.

In other words, it helps us to “optimize intelligent decision making by holding onto what’s important and letting go of what’s not.”

Think about it this way; is it easier to remember somebody’s face or their name? Which is the most important?

In a social setting, it is typically better to remember both but if we were part of the animal kingdom, remembering somebody as being a threat would mean our very lives. Remembering their name would be inconsequential.

The brain doesn’t automatically decide what we should remember and what we shouldn’t. It holds new memories but it sometimes overwrites old memories.

When the brain becomes cluttered with memories, they tend to conflict with each other and that can make it difficult to make important decisions.

That is why the brain tends to hold on to those big picture memories but they are becoming less important with the advent of technology.

As an example, at one time, we would have learned how to spell words but now, we just use Google if we don’t know how to spell them. We also tend to look everything up online, from how to change a showerhead to how to cook meatloaf for dinner.

If you forget everything, you may want to consider having a checkup but if you forget things on occasion, it’s perfectly okay.

The moral of the story is, the next time you forget something, just think of it as your brain doing what it was designed to do.

http://wetpaintlife.com/scientists-say-that-being-forgetful-is-actually-a-sign-you-are-unusually-intelligent/?utm_source=vn&utm_tracking=11&utm_medium=Social

The majority of the cells in the brain are no neurons, but Glia (from “glue”) cells, that support the structure and function of the brain. Astrocytes (“start cells”) are star-shaped glial cells providing many supportive functions for the neurons surrounding them, such as the provision of nutrients and the regulation of their chemical environment. Newer studies showed that astrocytes also monitor and modulate neuronal activity. For example, these studies have shown that astrocytes are necessary for the ability of neurons to change the strength of the connections between them, the process underlying learning and memory, and indeed astrocytes are also necessary for normal cognitive function. However, it is still unknown whether astrocytic activity is only necessary, or is it may also be sufficient to induce synaptic potentiation and enhance cognitive performance.

In a new study published in Cell, two graduate students, Adar Adamsky and Adi Kol, from Inbal Goshen’s lab, employed chemogenetic and optogenetic tools that allow specific activation of astrocytes in behaving mice, to explore their role in synaptic activity and memory performance. They found that astrocytic activation in the hippocampus, a brain region that plays an important role in memory acquisition and consolidation, potentiated the synaptic connections in this region, measured in brain slices. Moreover, in the intact brain, astrocytic activation enhanced hippocampal neuronal activity in a task-dependent way: i.e. only during when it was combined with memory acquisition, but not when mice were at their home cage with no meaningful stimuli. The ability of astrocytes to increase neuronal activity during memory acquisition had a significant effect on cognitive function: Specifically, astrocytic activation during learning resulted in enhanced memory in two memory tests. In contrast, direct neuronal activation in the hippocampus induced a non-selective increase in activity (during learning or in the home cage), and thus resulted in drastic memory impairment.

The results suggest that the memory enhancement induced by astrocytic activation during learning is not simply a result of a general increase in hippocampal neuronal activity. Rather, the astrocytes, which sense and respond to changes in the surrounding neuronal activity, can detect and specifically enhance only the neuronal activity involved in learning, without affecting the general activity. This may explain why general astrocytic activation improves memory performance, whereas a similar activation of neurons impairs it.

Memory is not a binary process (remember/don’t remember); the strength of a memory can vary greatly, either for the same memory or between different memories. Here, we show that activating astrocytes in mice with intact cognition improves their memory performance. This finding has important clinical implications for cognitive augmentation treatments. Furthermore, the ability of astrocytes to strengthen neuronal communication and improve memory performance supports the claim that astrocytes are able to take an active part in the neuronal processes underlying cognitive function. This perspective expands the definition of the role of astrocytes, from passive support cells to active cells that can modulate neural activity and thus shape behavior.

Link: https://www.cell.com/cell/pdf/S0092-8674(18)30575-0.pdf

https://elsc.huji.ac.il/content/article-month-june-2018-goshens-lab


by Nicolas Scherger

Dr. Thomas Hainmüller and Prof. Dr. Marlene Bartos of the Institute of Physiology of the University of Freiburg have established a new model to explain how the brain stores memories of tangible events. The model is based on an experiment that involved mice seeking a place where they received rewards in a virtual environment. The scientific journal “Nature” has published the study.

In the world of the mouse’s video game, the walls that depict a corridor four meters long are made up of green and blue patterned blocks. The floor is marked with turquoise dots. A short distance away, there’s a brown disc on the floor that looks like a cookie. That’s the symbol for the reward location. The mouse heads for it, gets there, and the symbol disappears. The next cookie promptly appears a bit further down the corridor. The mouse is surrounded by monitors and is standing on a styrofoam ball that is floating on compressed air and turns beneath the mouse when it runs. The ball makes it possible to transfer of the mouse’s movements to the virtual environment. If the mouse reaches the reward symbol, a straw is used to give it a drop of soy milk and stimulate it to form memories of its experiences in the virtual world. The mouse learns when, and at which location, it will receive a reward. It also learns how to locate itself and discriminate between different corridors in the video game.

Viewing the brain with a special microscope

“As the mouse is getting to know its environment, we use a special microscope to look from the outside into its brain and we record the activities of its nerve cells on video,” explains Thomas Hainmüller, a physician and doctoral candidate in the MD/PhD program of the Spemann Graduate School of Biology and Medicine (SGBM) of the University of Freiburg. He says that works because, in reality, the head of the mouse remains relatively still under the microscope as it runs through the virtual world of the video game. On the recordings, the mice’s genetically-manipulated nerve cells flash as soon as they become active. Hainmüller and Marlene Bartos, a Professor of Systemic and Cellular Neurobiology are using this method to investigate how memories are sorted and retrieved. “We repeatedly place the mouse in the virtual world on consecutive days,” says Hainmüller. “In that way, we can observe and compare the activity of the nerve cells in different stages of memory formation,” he explains.

Nerve cells encode places

The region of the brain called the hippocampus plays a decisive role in the formation of memory episodes – or memories of tangible experiences. Hainmüller and Bartos published that the nerve cells in the hippocampus create a map of the virtual world in which single neurons code for actual places in the video game. Earlier studies done at the Freiburg University Medical Center showed that nerve cells in the human hippocampus code video games in the same way. The cells become activated and flash when the mouse is at the respective place, otherwise they remain dark. “To our surprise, we found very different maps inside the hippocampus,” reports Hainmüller. In part, they provide an approximate overview of the position of the mouse in the corridor, yet they also consider time and context factors, and above all, information about in which of the corridors the mouse is located. The maps are also updated during the days of the experiment and as a result can be recognized as a learning process.

Better understanding of memory formation

The research team summarizes, saying that their observations provide a model that explains how activity of the nerve cells in the hippocampus can map the space, time and and context of memory episodes. The findings allow for better understanding of the biological processes that effect the formation of memory in the brain. Hainmüller says, “In the long term, we would like to use our results to contribute to the development of treatments to help people with neurological and psychiatric illnesses.”

Original publication
Thomas Hainmüller and Marlene Bartos (2018): Parallel emergence of stable and dynamic memory engrams in the hippocampus. In: Nature. doi: 10.1038/s41586-018-0191-2

https://www.pr.uni-freiburg.de/pm-en/online-magazine/research-and-discover/maps-made-of-nerve-cells

By Hilary Hurd Anyaso

Leading theories propose that sleep presents an opportune time for important, new memories to become stabilized. And it’s long been known which brain waves are produced during sleep. But in a new study, researchers set out to better understand the brain mechanisms that secure memory storage.

The team from Northwestern and Princeton universities set out to find more direct and precisely timed evidence for the involvement of one particular sleep wave — known as the “sleep spindle.”

In the study, sleep spindles, described as bursts of brain activity typically lasting around one second, were linked to memory reactivation. The paper, “Sleep spindle refractoriness segregates periods of memory reactivation,” published today in the journal Current Biology.

“The most novel aspect of our study is that we found these spindles occur rhythmically — about every three to six seconds — and this rhythm is related to memory,” said James W. Antony, first author of the study and a postdoctoral fellow in Princeton’s Computational Memory Lab.

Three experiments explored how recent memories are reactivated during sleep. While volunteers took an afternoon nap, sound cues were surreptitiously played. Each was linked to a specific memory. The researchers’ final experiment showed that if cues were presented at opportune times such that spindles could follow them, the linked memories were more likely to be retained. If they were presented when a spindle was unlikely to follow, the linked memories were more likely to be forgotten.

“One particularly remarkable aspect of the study was that we were able to monitor spindles moment by moment while people slept,” said Ken A. Paller, senior author of the study and professor of psychology at Northwestern’s Weinberg College of Arts and Sciences. “Therefore, we could know when the brain was most ready for us to prompt memory reactivation.”
If the researchers reminded people of a recently learned fact, a spindle would likely be evident in the cerebral cortex, and memory for that information would be improved, added Paller, also director of Northwestern’s Cognitive Neuroscience Program.

“In memory research, we know it’s important to segregate experiences while you’re awake so that everything doesn’t just blend together,” said Antony, who worked in Paller’s lab at Northwestern as a doctoral student. “If that happens, you may have difficulty retrieving information because so many things will come to mind at once. We believe the spindle rhythmicity shown here might play a role in segregating successive memory reactivations from each other, preventing overlap that might cause later interference between memories.”

Ultimately, the researchers’ goal is to understand how sleep affects memory under natural conditions and how aging or disease can impact these functions.

“With that goal in mind, we’ve helped elucidate the importance of sleep spindles more generally,” Antony said.

Paller said they are on the trail of the physiology of memory reactivation.

“Future work will be needed to see how spindles fit together with other aspects of the physiology of memory and will involve other types of memory testing and other species,” Paller said.

In addition to Antony and Paller, co-authors are Luis Piloto, Margaret Wang, Paula Pacheco and Kenneth A. Norman, all of Princeton.

https://news.northwestern.edu/stories/2018/may/bursts-of-brain-activity-linked-to-memory-reactivation/

By Rachael Rettner

Many people tend to look back on the past with rose-colored glasses, remembering the good times and the good feelings…while forgetting the bad.

But a new study suggests that heavy marijuana users may have some trouble letting go of negative emotions tied to memories — a phenomenon that’s also seen in people with depression. Earlier research has also linked marijuana use with depression.

Although the new results are very preliminary, the findings, presented here on Friday (May 25) at the annual meeting of the Association for Psychological Science, may offer clues about the link between marijuana use and depression.

Rose-colored memories

The study explored a psychological phenomenon called “fading affect bias,” in which people tend to hold on to positive feelings tied to their memories more than they hold on to negative feelings. In other words, negative feelings related to our memories fade faster than positive ones.

Psychologists have hypothesized that this phenomenon, which is generally seen in people without mental health conditions, may serve as a sort of “psychological immune system,” said study lead author Daniel Pillersdorf, a graduate student in psychology at the University of Windsor in Ontario. This may be “so that we think more pleasantly in general, and don’t have that cognitive burden of holding on to negative emotions associated with memories,” Pillersdorf said.

Some previous studies have suggested that this fading affect bias may be different for people who use drugs, but no studies have looked at whether marijuana use could affect this phenomenon.

In the new study, the researchers analyzed information from 46 heavy marijuana users — most of whom used the drug at least four times a week — and 51 people who didn’t use marijuana. Participants were asked to recall, and provide written descriptions of, three pleasant memories and three unpleasant memories from the past year. The participants were then asked to rate the intensity of emotion tied to those memories, on a scale of negative 10, meaning extremely unpleasant, to positive 10, or extremely pleasant. They rated their emotions both at the time the memory was made, and at the current time. (Marijuana users were not under the influence at the time the researchers asked them the questions.)

The researchers found that both marijuana users and non-users showed fading affect bias, but for marijuana users, the fading was a lot less.

“They were hanging on to that unpleasant affect over time, much more” than non-users, Pillersdorf told Live Science. “They were less able … to shed that unpleasantness associated with their memories.”

The study also found that marijuana users tended to recall life events in more general terms than specific ones. For example, when asked about a happy event in the past year, marijuana users were more likely to respond with general or broad answers such as “I went on vacation,” rather than recalling a specific event or day, such as “I attended my college graduation.” This phenomenon is known as over-general autobiographical memory, and it’s also linked with depression, Pillersdorf said.

It’s important to note that the new study found only an association and cannot determine why marijuana users show less fading affect bias, and more overgeneral memory, than non-users.

Link with depression?

Even so, the new findings agree with previous research that has found a link between heavy marijuana use and depression. However, researchers don’t know why marijuana and depression are linked — it could be that marijuana use plays a role in developing depression, or that people who are already depressed are more likely to use the drug. [7 Ways Marijuana May Affect the Brain]

Based on the new findings, one hypothesis is that the decreased “fading” of negative memories in marijuana users could be contributing to the development or continuing of depression, Pillersdorf said. “It may be that, chronic or frequent cannabis use is putting [a person] more at risk for the development or continuing of depression,” he said. However, Pillersdorf stressed that this is just a hypothesis that would need to be investigated with future research.

To further investigate the link, researchers will need to study marijuana users and non-users over long periods of time. For example, researchers could start with people in their late teens or early 20s, who don’t have depression, and see if those who use marijuana frequently are more likely to eventually develop depression than non-users.

Additional studies could also investigate whether other substances have an effect on fading affect bias, Pillersdorf said.

The study has not yet been published in a peer-reviewed journal.

https://www.livescience.com/62679-marijuana-negative-memories.html?utm_source=notification