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Does a person's brain still contain a record of daily events?

Does a person's brain still contain a record of daily events?

Does a person's brain have a record of every event that happened during a person's lifetime? Is it possible to recall any of those events and is it possible to recall those events in detail?

For example, I almost drowned when I was a child. I know this happened and can remember bits of the event but I don't remember all the details. Is that complete memory still stored?


No. I don't think so. There are many arguments for why this is not the case.

  • A common understanding of human memory is that it is part of an information processing system: attention, sensation, perception, interpretation, memory consolidation, forgetting, and memory recall. In some sense all these represent possible points of failure. Thus, we can fail to attend to an event in the first place, we can misunderstand the nature of an event, or memories can be temporarily inaccessible.
  • Building on the idea of the information processing system, it is important to recognise the huge subjective component to the experience of an "event". This links closely with philosophical questions about the nature of reality. However, regardless of the nature of the truth of external reality, it is clear that human experience is imbued with meaning and is experienced through various cognitive schemas. Thus, the "objective event", whatever that might be, is often never represented in the first place.
  • Another perspective is that memory has been shaped by the adaptive needs of humans. In such a context, memory consumes resources. Memory also needs to efficiently serve our needs. From such a perspective forgetting of irrelevant memories and consolidation of life saving and life improving memories is important to our adaptation. For example, this is an argument for the benefits of a forgetting curve whereby recent memories are recalled better than distal memories; recent memories are more likely to be relevant to current behaviour.
  • There is so much research to show the failures of human memory in even short term contexts. For example, check out some of the eye witness testimony research of Elizabeth Loftus to see how poor people are at recalling details even short term. The entire field of memory research extensively documents failure of recall and biases in recall.

Despite all this, there are also many times where people can not currently recall something that is stored in long term memory. See for example discussions of tip of the tongue phenomena, spreading activation, fan out effect and so on.


(1) There are different kinds of memory:

  • a "sensory" (e.g. visual) memory of events as they happened
  • a verbal memory, i.e. the knowledge that something has happened (verbalization being the result of higher cognitive processing or "reflection")
  • a behavioral memory, i.e. a specific reaction to certain stimuli that does not appear in individuals that did not experience the relevant trauma

The purposes of memory are correct and efficient future behavior. A detailed sensoric memory is not helpful in achieving these purposes, so it is usually not retained.

Verbal encoding becomes more likely in older children (older than 28 to 36 months) and is better in girls. Children of all ages preserve a behavioral memory. (Terr, 1988)

(2) Traumatic and negative life events are less well remembered than positive life events (Byrne, Hyman & Scott, 2001), and it seems that memory is correlated to the type of trauma. In one study (Williams, 1994), 38% of abused women had no memory of that (documented) abuse. Forgetting the abuse was more likely, if the perpretrator was part of the girls family. I would interpret this as the trauma being more severe, if the child's trust was broken. Forgetting this may be a coping strategy (see 3, below).

(3) Forgetting of traumatic events seems, in part, to be due to these traumatic events to "fall out of" and "not fit into" the individuals world view (Janoff-Bulman, 1989). Whenever we experience something new, we have to either adapt our idea of the world to include this new experience, or we can, among other strategies, deny, ignore, or simply forget, that it happened. In the case of childhood abuse by close relatives, accepting the event as a fact, would result in the child loosing its family and all trust in the world. It would be unable to survive. Forgetting the trauma maintains a world that can be lived in. Deliberate forgetting can be found in victims of genocide (Buckley-Zistel, 2006). Forgetting can be willfully induced (Joslyn & Oakes, 2005).

There's a wealth of research into forgetting of traumatic life events.


There are individuals who possess extraordinary memory ability, sometimes called eidetic memory. With specific reference to your question, a woman in Los Angeles has an extraordinary ability to recall autobiographical events from her past. You can read the Wired article of her story here.

At the scientists' behest, for example, she recalled-without warning and in just 10 minutes-what she'd done on every Easter since 1980. "April 6, 1980: 9th grade, Easter vacation ends. April 19, 1981: 10th grade, new boyfriend, H. April 11, 1982: 11th grade, grandparents visiting for Passover… "

Her ability extends to certain momentous cultural events, such as disasters.

She instantly retrieves from memory the exact dates of the explosions of space shuttle Challenger and Pan Am flight 103 over Lockerbie, Scotland. She remembers not just that September 25, 1978, was when a PSA flight crashed in San Diego but also that the jet collided with a Cessna. She can go in either direction, disaster to date or date to disaster. When I say "January 13, 1982," Price has no trouble recalling the Air Florida flight that plummeted into the Potomac.

One theory of her astounding memory is that she obsessively thinks about events after they happen, which leads to more effective encoding and strengthening of the memory for that event. This seems to be a key distinction between her and a person of average memory - if you didn't encode an event completely when it happened you are unlikely to be able to recall it completely later. Trauma, such as nearly drowning, can either enhance or degrade this process.

If you are curious, a great book that goes over our many memory failings is "The Seven Sins of Memory" by Daniel Schacter. Highly recommended.


This Is What Sugar Does To Your Brain

We know that too much sugar is bad for our waistlines and our heart health, but now there's mounting evidence that high levels of sugar consumption can also have a negative effect on brain health -- from cognitive function to psychological wellbeing.

While sugar is nothing to be too concerned about in small quantities, most of us are simply eating too much of it. The sweet stuff -- which also goes by names like glucose, fructose, honey and corn syrup -- is found in 74 percent of packaged foods in our supermarkets. And while the Word Health Organization recommends that only 5 percent of daily caloric intake come from sugar, the typical American diet is comprised of 13 percent calories from sugar.

It's easy to see how we can get hooked on sugar. However, we should be aware of the risks that a high-sugar diet poses for brain function and mental well-being.

Here's what you need to know about how overconsumption of sugar could wreak havoc on your brain.

It creates a vicious cycle of intense cravings.

When a person consumes sugar, just like any food, it activates the tongue's taste receptors. Then, signals are sent to the brain, lighting up reward pathways and causing a surge of feel-good hormones, like dopamine, to be released. Sugar "hijacks the brain’s reward pathway," neuroscientist Jordan Gaines Lewis explained. And while stimulating the brain's reward system with a piece of chocolate now and then is pleasurable and probably harmless, when the reward system is activated too much and too frequently, we start to run into problems.

"Over-activating this reward system kickstarts a series of unfortunate events -- loss of control, craving, and increased tolerance to sugar," neuroscientist Nicole Avena explained in a TED-Ed video.

In fact, research has shown that the brains of obese children actually light up differently when they taste sugar, reflecting an elevated "food reward" response. This suggests that their brain circuitry may predispose these children to a lifetime of intense sugar cravings.

It impairs memory and learning skills.

A 2012 study on rats, conducted by researchers at UCLA, found that a diet high in fructose (that's just another word for sugar) hinders learning and memory by literally slowing down the brain. The researchers found that rats who over-consumed fructose had damaged synaptic activity in the brain, meaning that communication among brain cells was impaired.

Heavy sugar intake caused the rats to develop a resistance to insulin -- a hormone that controls blood sugar levels and also regulates the function of brain cells. Insulin strengthens the synaptic connections between brain cells, helping them to communicate better and thereby form stronger memories. So when insulin levels in the brain are lowered as the result of excess sugar consumption, cognition can be impaired.

"Insulin is important in the body for controlling blood sugar, but it may play a different role in the brain," Dr. Fernando Gomez-Pinilla, the study's lead author, said in a statement. "Our study shows that a high-fructose diet harms the brain as well as the body. This is something new."

It may cause or contribute to depression and anxiety.

If you've ever experienced a sugar crash, then you know that sudden peaks and drops in blood sugar levels can cause you to experience symptoms like irritability, mood swings, brain fog and fatigue. That's because eating a sugar-laden donut or drinking a soda causes blood sugar levels to spike upon consumption and then plummet. When your blood sugar inevitably dips back down (hence the "crash"), you may find yourself feeling anxious, moody or depressed.

Sugar-rich and carb-laden foods can also mess with the neurotransmitters that help keep our moods stable. Consuming sugar stimulates the release of the mood-boosting neurotransmitter serotonin. Constantly over-activating these serotonin pathways can deplete our limited supplies of the neurotransmitter, which can contribute to symptoms of depression, according to Dr. Datis Kharrazian, functional medicine expert and author of Why Isn't My Brain Working?.

Chronically high blood sugar levels have also been linked to inflammation in the brain. And as some research has suggested, neuroinflammation may be one possible cause of depression.

Teenagers may be particularly vulnerable to the effects of sugar on mood. A recent study on adolescent mice, conducted by researchers at Emory University School of Medicine, found a diet high in sugar to contribute to depression and anxiety-like behavior.

Research has also found that people who eat a standard American diet that's high in processed foods -- which typically contain high amounts of saturated fat, sugar and salt -- are at an increased risk for developing depression, compared to those who eat a whole foods diet that's lower in sugar.

It's a risk factor for age-related cognitive decline and dementia.

A growing body of research suggests that a sugar-heavy diet could increase risk for developing Alzheimer's disease. A 2013 study found that insulin resistance and blood glucose levels -- which are hallmarks of diabetes -- are linked with a greater risk for developing neurodegenerative disorders like Alzheimer's. The research “offers more evidence that the brain is a target organ for damage by high blood sugar,” endocrinologist Dr. Medha Munshi told the New York Times.

Some researchers, in fact, have even referred to Alzheimer's as "Type 3 Diabetes" -- which suggests that diet may have some role in an individual's risk for developing the disease.

These recognizable-anywhere cans are bad news: They contain 23.5 ounces, nearly three times the suggested serving size for the tea inside. With 90 calories per 8 ounces, finishing an entire can adds up to almost 270.


How Memories Are Made…

The brain has specific areas in which information is stored or that operate certain areas of the body. The ability to tap the left forefinger is located in the right side of the brain for example. The left side of the brain contains language capability while the right side contains our ability to view objects in space. Memory for faces is located in the right side of the brain while the name of the individual is located in the left side of the brain. This is why we can recognize an old school mate almost immediately but the brain may require several seconds to obtain the name. If we are anxious, this impairs recall, and the name won’t come to us for several minutes after the recognition.

The brain contains multiple memory systems. Remembering how to ride a bicycle, known as procedural or implicit memory, involves a different memory system than remembering the year Columbus discovered America, known as declarative or explicit memory. Studies tell us we can have two types of memory for the same situation, especially if the situation/experience is one associated with strong emotions. For a single experience (traumatic event, good event, emotional experience, etc.) we can have an explicit memory — a memory of the details of the experience — and an implicit memory, a memory of the emotions connected to the experience. Implicit memory has also been called “emotional memory” because it contains the memory of the physiological response at the time of the experience. This physiological response may include increased blood pressure, higher respiration, muscle tension, anxiety, fearfulness, and other reactions associated with fear, terror, fright, or even joy.

In neurological studies, the memory for details (explicit memory) has been linked to the brain structure known as the hippocampus. Memories made by the hippocampus are very much under our conscious control, as when remembering the words to “Jingle Bells” or our birthday. Emotional or unconscious memories are linked to the brain structure known as the amygdala. Some of these unconscious (out of our conscious control or not purposefully remembered) memories are procedural, as when the brain memorizes how to ride a bicycle — you don’t have to think about it, you simply hop on and ride away. Other emotional memories are a record of the physiological/emotional response we have experienced during an event.

When we experience a very emotional event, the brain records not only the details of the experience (where we were, when, who was there, what happened, etc.) but the emotions we experienced at the time as well. The entire memory of an emotional event (an assault, an automobile accident, a wedding, death of a loved one, a combat experience, etc.) is actually remembered by two systems in the brain and stored in two separate areas of the brain.

When we remember horrible or traumatic events, the brain often remembers both the details and emotional memory at the same time. If we remember the details of being assaulted, we will also experience the feelings we had at that time — the increased heart rate, fearfulness, panic, and desperation.

As we will soon review, the brain has the ability to remember the details and the emotions both on purpose and by accident. The brain also has the ability to remember one part of the memory without another part surfacing. As we go through life, the brain may also have an experience that prompts an emotional memory but does not bring up the details of the experience.

Detail memory will often see someone at a distance and offer a “best guess” as to their identity. As the person moves closer, the “best guess” offered by the brain may be true or false. Emotional memory works the same way, looking at a current situation/experience and offering a “best guess” by remembering a previous emotional situation. This is the reality of Post-Traumatic Stress Disorder (PTSD) and emotional trauma. We may emotionally relive a combat memory when we hear a car backfire or emotionally feel as if we are being assaulted if someone jokingly grabs us from behind.

It is hoped that this article will explain how emotional memory works and how it can be managed for those who are haunted by the experiences of their past.


Abstract

To enable the impact of neuroscientific insights on our daily lives, careful translation of research findings is required. However, neuroscientific terminology and common-sense concepts are often hard to square. For example, when neuroscientists study lying to allow the use of brain scans for lie-detection purposes, the concept of lying in the scientific case differs considerably from the concept in court. Furthermore, lying and other cognitive concepts are used unsystematically and have an indirect and divergent mapping onto brain activity. Therefore, scientific findings cannot inform our practical concerns in a straightforward way. How then can neuroscience ultimately help determine if a defendant is legally responsible, or help someone understand their addiction better? Since the above-mentioned problems provide serious obstacles to move from science to common-sense, we call this the 'translation problem'. Here, we describe three promising approaches for neuroscience to face this translation problem. First, neuroscience could propose new ɿolk-neuroscience' concepts, beyond the traditional folk-psychological array, which might inform and alter our phenomenology. Second, neuroscience can modify our current array of common-sense concepts by refining and validating scientific concepts. Third, neuroscience can change our views on the application criteria of concepts such as responsibility and consciousness. We believe that these strategies to deal with the translation problem should guide the practice of neuroscientific research to be able to contribute to our day-to-day life more effectively.


New study suggests we have 6,200 thoughts every day

A new study from psychologists at Queen's University in Kingston, Ontario reports observations of the transition from one thought to another in fMRI brain scans. Though the researchers didn't detect the content of our thoughts, their method allowed them to count each one. Referred to as "thought worms," the team says that the average human has 6,200 thoughts per day.

"What we call 'thought worms' are adjacent points in a simplified representation of activity patterns in the brain," said senior study author Jordan Poppenk. "The brain occupies a different point in this 'state space' at every moment. When a person moves onto a new thought, they create a new thought worm that we can detect with our methods."

The study was recently published in the journal Nature Communications.

Not so much the 'what' as the 'when'

There's been a fair amount of research devoted to understanding what a person is thinking based on observations of brain activity. However, the only way to know what a particular pattern of brain activity means would be to recognize its similarity to a brain-activity template known to represent that type of thought. Few such templates are available thus far, and they're time-consuming and expensive to produce.

Poppenk and his MA student Julie Tseng went another way. "We had our breakthrough by giving up on trying to understand what a person is thinking about, and instead focusing on when they have moved on," said Poppenk. He adds, "Our methods help us detect when a person is thinking something new, without regard to what the new thought is. You could say that we've skipped over vocabulary in an effort to understand the punctuation of the language of the mind."

A thought, says the study, is generally viewed by researchers as a mental state, a "transient cognitive or emotional state of the organism." Poppenk says that since such states are relatively stable in terms of brain activity — sustained attention being most closely associated with the angular gyrus — it's possible to identify transitions between one state and another using fMRI data from individual participants. "We argue that neural meta-state transitions can serve as an implicit biological marker of new thoughts," the study reads.

The researchers verified their hypothesis using fMRI scans from two groups of participants: some who were watching movies, and others who were in a resting state. "Transitions detected by our methods predict narrative events, are similar across task and rest, and are correlated with activation of regions associated with spontaneous thought."

"Being able to measure the onset of new thoughts gives us a way," explains Poppenk, "to peek into the 'black box' of the resting mind — to explore the timing and pace of thoughts when a person is just daydreaming about dinner and otherwise keeping to themselves."

The use of fMRIs is key, he adds. "Thought transitions have been elusive throughout the history of research on thought, which has often relied on volunteers describing their own thoughts, a method that can be notoriously unreliable."

Spontaneous thought and attention regions distinguish transitions from meta-stability

Have you thought your 6,200 thoughts yet today?

While we average 6,200 thought worms a day, Poppenk anticipates further research tracking the manner in which the number of daily thoughts an individual has may change over the course of a lifetime. Likewise, he's interested in investigating potential associations between how quickly a person jumps from one thought to another and other mental and personality traits. "For example," he says, "how does mentation rate — the rate at which thought transitions occur — relate to a person's ability to pay attention for a long period?"

In addition, the researcher wonders if "measures of thought dynamics serve a clinical function? For example, our methods could possibly support early detection of disordered thought in schizophrenia, or rapid thought in ADHD or mania."

"We think the methods offer a lot of potential," Poppenk says. "We hope to make heavy use of them in our upcoming work."


Transsexual differences caught on brain scan

Differences in the brain’s white matter that clash with a person’s genetic sex may hold the key to identifying transsexual people before puberty. Doctors could use this information to make a case for delaying puberty to improve the success of a sex change later.

Medics are keen to find concrete physical evidence to help those children who feel they are trapped in the body of the opposite sex. One key brain region involved is the BSTc, an area of grey matter. But the region is too small to scan in a living person so differences have only been picked up at post-mortem.

Antonio Guillamon‘s team at the National University of Distance Education in Madrid, Spain, think they have found a better way to spot a transsexual brain. In a study due to be published next month, the team ran MRI scans on the brains of 18 female-to-male transsexual people who’d had no treatment and compared them with those of 24 males and 19 females.

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They found significant differences between male and female brains in four regions of white matter – and the female-to-male transsexual people had white matter in these regions that resembled a male brain (Journal of Psychiatric Research, DOI&colon 10.1016/j.jpsychires.2010.05.006). “It’s the first time it has been shown that the brains of female-to-male transsexual people are masculinised,” Guillamon says.

In a separate study, the team used the same technique to compare white matter in 18 male-to-female transsexual people with that in 19 males and 19 females. Surprisingly, in each transsexual person’s brain the structure of the white matter in the four regions was halfway between that of the males and females (Journal of Psychiatric Research, DOI&colon 10.1016/j.jpsychires.2010.11.007). “Their brains are not completely masculinised and not completely feminised, but they still feel female,” says Guillamon.

Guillamon isn’t sure whether the four regions are at all associated with notions of gender, but Ivanka Savic-Berglund at the Karolinska Institute in Stockholm, Sweden, thinks they might be. One of the four regions – the superior longitudinal fascicle – is particularly interesting, she says. “It connects the parietal lobe [involved in sensory processing] and frontal lobe [involved in planning movement] and may have implications in body perception.”

A 2010 study of 121 transgender people found that 38 per cent realised they had gender variance by age 5. White matter differences could provide independent confirmation that such children might benefit from treatment to delay puberty.

A study by Sean Deoni‘s team at King’s College London suggests it may soon be possible to look for these differences in such children. Deoni’s team adapted an MRI scanner to be as quiet as possible so it could be used to monitor the development of white matter in sleeping infants. Using new image analysis software they could track when and where myelin – the neuron covering that makes white matter white – was laid down (Journal of Neuroscience, vol 31, p 784). Although the sample was too small to identify any gender differences in development, Deoni expects to see differences developing in the brain “by 2 or 3 years of age”.

Guillamon thinks such scans may not help in all cases. “Research has shown that white matter matures during the first 20 to 30 years of life,” he says. “People may experience early or late onset of transsexuality and we don’t know what causes this difference.”


You say your primary motivation in writing this book is to inspire compassion through scientific understanding. Can you explain the linkage?

There's a much stronger link than people think. It’s about asking ourselves what does it mean to be a good scientist? Too often we think science is a methodology, a process. Our idea is that it's a way of being that enables you to step into uncertainty. And celebrating doubt, stepping into uncertainty, is fundamental to being compassionate.

It's not so much that I'm doing research into compassion. I'm hoping that compassion comes out of the research, by making people part of the process of understanding their own perceptions. Perception underpins everything we think, do, believe, know, or love. Once you understand that, there are consequences like compassion, respect, creativity, choice, community.


Here's What Happens to Your Brain When You Die

You might picture yourself walking through a field, or surrounded by loved ones. Or perhaps making your way down a long, dark tunnel, towards a brilliant, beckoning light.

When the end comes, what you experience will be a veiled secret known only to you – but whatever it is, scientists say those closing moments of consciousness could be powered by something amazing and mysterious taking place inside your brain.

In 2013, researchers at the University of Michigan found that after clinical death occurred in rats, their brain activity actually flared, revealing electrical signatures of consciousness that exceeded levels found in the animals' waking state.

"We reasoned that if near-death experience stems from brain activity, neural correlates of consciousness should be identifiable in humans or animals even after the cessation of cerebral blood flow," said one of the team, neurologist Jimo Borjigin.

And that's exactly what they detected, with anaesthetised rats displaying a surge of highly synchronised brain activity within 30 seconds of an induced cardiac arrest, consistent with patterns you'd see in a highly aroused brain.

The phenomenon detected was a revelation, to the extent it may disprove the notion that just because blood flow has ceased as a result of clinical death, the brain must necessarily be rendered simultaneously inert.

"This study tells us that reduction of oxygen or both oxygen and glucose during cardiac arrest can stimulate brain activity that is characteristic of conscious processing," said Borjigin.

"It also provides the first scientific framework for the near-death experiences reported by many cardiac arrest survivors."

Of course, while the findings do establish a new framework for interpreting where near-death experiences might come from, it doesn't necessarily follow that humans would undergo the same cognitive flare as rats journeying beyond the veil.

But if our brains somehow surge in the same way, it could help to explain the sense of awareness reported by many people who are successfully resuscitated in medical emergencies.

Somebody who knows a bit about that is critical care researcher Sam Parnia from Stony Brook University, who in 2014 released the world's largest study examining near-death experiences and out-of-body experiences.

From interviews with more than 100 survivors of cardiac arrest, 46 percent retained memories of their brush with death, centred around a number of common themes, including bright lights, family, and fear.

But even more intriguingly, two of the patients were able to recall events related to their resuscitation that happened after they had died, which, according to conventional views about consciousness beyond clinical death, shouldn't have been possible.

"We know the brain can't function when the heart has stopped beating, but in this case conscious awareness appears to have continued for up to three minutes into the period when the heart wasn't beating," Parnia told The National Post, "even though the brain typically shuts down within 20 to 30 seconds after the heart has stopped."

It sounds amazing, but it's worth noting that the phenomenon was only reported by 2 percent of patients, and Parnia himself even later admitted "the easiest explanation is that this is probably an illusion".

That 'illusion' could be borne out of a neurological response to physiological stress during cardiac events. In other words, a cognitive experience preceding – not following – the clinical death itself, and which is later remembered by the patient.

Certainly, that's what many in the neuroscience community tend to think.

"Look, I'm sceptical," neurologist Cameron Shaw from Deakin University in Australia told Vice earlier in the year.

"I think out-of-body experiences have been debunked, just because the mechanisms that produce sight and record memories are inoperative."

According to Cameron, because the brain's blood supply is pumped from underneath, the brain would die from the top downwards.

"Our sense of self, our sense of humour, our ability to think ahead – that stuff all goes within the first 10 to 20 seconds," Julian Morgans reported for Vice.

"Then, as the wave of blood-starved brain cells spread out, our memories and language centres short out, until we're left with just a core."

Not a very encouraging outlook, but it's worth noting that it also doesn't accord with the experience of rats – and scientists are still finding evidence of surprising biological processes that continue to thrive even days after death stakes its claim.

All up, we're out of answers, and while science has given us some fascinating insights into what the brain's final moments might be, the research isn't yet conclusive.

As we've said once before, when the curtain is drawn, we really have no firm idea of what it's going to look or feel like. But we know for sure we're all eventually going to find out.


Study shows stronger brain activity after writing on paper than on tablet or smartphone

A study of Japanese university students and recent graduates has revealed that writing on physical paper can lead to more brain activity when remembering the information an hour later. Researchers say that the unique, complex, spatial and tactile information associated with writing by hand on physical paper is likely what leads to improved memory.

"Actually, paper is more advanced and useful compared to electronic documents because paper contains more one-of-a-kind information for stronger memory recall," said Professor Kuniyoshi L. Sakai, a neuroscientist at the University of Tokyo and corresponding author of the research recently published in Frontiers in Behavioral Neuroscience. The research was completed with collaborators from the NTT Data Institute of Management Consulting.

Contrary to the popular belief that digital tools increase efficiency, volunteers who used paper completed the note-taking task about 25% faster than those who used digital tablets or smartphones.

Although volunteers wrote by hand both with pen and paper or stylus and digital tablet, researchers say paper notebooks contain more complex spatial information than digital paper. Physical paper allows for tangible permanence, irregular strokes, and uneven shape, like folded corners. In contrast, digital paper is uniform, has no fixed position when scrolling, and disappears when you close the app.

"Our take-home message is to use paper notebooks for information we need to learn or memorize," said Sakai.

In the study, a total of 48 volunteers read a fictional conversation between characters discussing their plans for two months in the near future, including 14 different class times, assignment due dates and personal appointments. Researchers performed pre-test analyses to ensure that the volunteers, all 18-29 years old and recruited from university campuses or NTT offices, were equally sorted into three groups based on memory skills, personal preference for digital or analog methods, gender, age and other aspects.

Volunteers then recorded the fictional schedule using a paper datebook and pen, a calendar app on a digital tablet and a stylus, or a calendar app on a large smartphone and a touch-screen keyboard. There was no time limit and volunteers were asked to record the fictional events in the same way as they would for their real-life schedules, without spending extra time to memorize the schedule.

After one hour, including a break and an interference task to distract them from thinking about the calendar, volunteers answered a range of simple (When is the assignment due?) and complex (Which is the earlier due date for the assignments?) multiple choice questions to test their memory of the schedule. While they completed the test, volunteers were inside a magnetic resonance imaging (MRI) scanner, which measures blood flow around the brain. This is a technique called functional MRI (fMRI), and increased blood flow observed in a specific region of the brain is a sign of increased neuronal activity in that area.

Participants who used a paper datebook filled in the calendar within about 11 minutes. Tablet users took 14 minutes and smartphone users took about 16 minutes. Volunteers who used analog methods in their personal life were just as slow at using the devices as volunteers who regularly use digital tools, so researchers are confident that the difference in speed was related to memorization or associated encoding in the brain, not just differences in the habitual use of the tools.

Volunteers who used analog methods scored better than other volunteers only on simple test questions. However, researchers say that the brain activation data revealed significant differences.

Volunteers who used paper had more brain activity in areas associated with language, imaginary visualization, and in the hippocampus -- an area known to be important for memory and navigation. Researchers say that the activation of the hippocampus indicates that analog methods contain richer spatial details that can be recalled and navigated in the mind's eye.

"Digital tools have uniform scrolling up and down and standardized arrangement of text and picture size, like on a webpage. But if you remember a physical textbook printed on paper, you can close your eyes and visualize the photo one-third of the way down on the left-side page, as well as the notes you added in the bottom margin," Sakai explained.

Researchers say that personalizing digital documents by highlighting, underlining, circling, drawing arrows, handwriting color-coded notes in the margins, adding virtual sticky notes, or other types of unique mark-ups can mimic analog-style spatial enrichment that may enhance memory.

Although they have no data from younger volunteers, researchers suspect that the difference in brain activation between analog and digital methods is likely to be stronger in younger people.

"High school students' brains are still developing and are so much more sensitive than adult brains," said Sakai.

Although the current research focused on learning and memorization, the researchers encourage using paper for creative pursuits as well.

"It is reasonable that one's creativity will likely become more fruitful if prior knowledge is stored with stronger learning and more precisely retrieved from memory. For art, composing music, or other creative works, I would emphasize the use of paper instead of digital methods," said Sakai.


Why are memories attached to emotions so strong?

Memories linked with strong emotions often become seared in the brain.

Most people can remember where they were on 9/11, or what the weather was like on the day their first child was born. Memories about world events on Sept 10, or lunch last Tuesday, have long been erased.

Why are memories attached to emotions so strong?

"It makes sense we don't remember everything," says René Hen, PhD, professor of psychiatry and neuroscience at Columbia University Vagelos College of Physicians and Surgeons. "We have limited brain power. We only need to remember what's important for our future wellbeing."

Fear, in this context, is not just a momentary feeling but a learning experience critical to our survival. When a new situation makes us fearful, the brain records the details in our neurons to help us avoid similar situations in the future, or use appropriate caution.

What's still a mystery is why these memories, recorded by the brain's hippocampus, become so strong.

To find out, Hen and Jessica Jimenez, an MD/PhD student at Columbia, placed mice into new, frightening environments and recorded the activity of hippocampal neurons that reach out to the brain's fear center (the amygdala). The neurons' activity was also recorded a day later when the mice tried to retrieve memories of the experience.

Unsurprisingly, neurons that respond to the frightening environment send that information to the brain's fear center.

"What was surprising was that these neurons were synchronized when the mouse later recalled the memory," Hen says.

"We saw that it's the synchrony that is critical to establish the fear memory, and the greater the synchrony, the stronger the memory," Jimenez adds. "These are the types of mechanisms that explain why you remember salient events."

How and when synchronization occurs is still unknown, but the answer could reveal the inner workings of the brain that create lifelong memories and lead to new treatments for posttraumatic stress disorder.

"In people with PTSD, many similar events remind them of the original frightening situation," Hen says, "and it's possible that synchronization of their neurons has become too strong."

"We're really trying to dig into the mechanisms of how emotional memories form to find better treatments for people with PTSD and memory disorders in general."


How Memories Are Made…

The brain has specific areas in which information is stored or that operate certain areas of the body. The ability to tap the left forefinger is located in the right side of the brain for example. The left side of the brain contains language capability while the right side contains our ability to view objects in space. Memory for faces is located in the right side of the brain while the name of the individual is located in the left side of the brain. This is why we can recognize an old school mate almost immediately but the brain may require several seconds to obtain the name. If we are anxious, this impairs recall, and the name won’t come to us for several minutes after the recognition.

The brain contains multiple memory systems. Remembering how to ride a bicycle, known as procedural or implicit memory, involves a different memory system than remembering the year Columbus discovered America, known as declarative or explicit memory. Studies tell us we can have two types of memory for the same situation, especially if the situation/experience is one associated with strong emotions. For a single experience (traumatic event, good event, emotional experience, etc.) we can have an explicit memory — a memory of the details of the experience — and an implicit memory, a memory of the emotions connected to the experience. Implicit memory has also been called “emotional memory” because it contains the memory of the physiological response at the time of the experience. This physiological response may include increased blood pressure, higher respiration, muscle tension, anxiety, fearfulness, and other reactions associated with fear, terror, fright, or even joy.

In neurological studies, the memory for details (explicit memory) has been linked to the brain structure known as the hippocampus. Memories made by the hippocampus are very much under our conscious control, as when remembering the words to “Jingle Bells” or our birthday. Emotional or unconscious memories are linked to the brain structure known as the amygdala. Some of these unconscious (out of our conscious control or not purposefully remembered) memories are procedural, as when the brain memorizes how to ride a bicycle — you don’t have to think about it, you simply hop on and ride away. Other emotional memories are a record of the physiological/emotional response we have experienced during an event.

When we experience a very emotional event, the brain records not only the details of the experience (where we were, when, who was there, what happened, etc.) but the emotions we experienced at the time as well. The entire memory of an emotional event (an assault, an automobile accident, a wedding, death of a loved one, a combat experience, etc.) is actually remembered by two systems in the brain and stored in two separate areas of the brain.

When we remember horrible or traumatic events, the brain often remembers both the details and emotional memory at the same time. If we remember the details of being assaulted, we will also experience the feelings we had at that time — the increased heart rate, fearfulness, panic, and desperation.

As we will soon review, the brain has the ability to remember the details and the emotions both on purpose and by accident. The brain also has the ability to remember one part of the memory without another part surfacing. As we go through life, the brain may also have an experience that prompts an emotional memory but does not bring up the details of the experience.

Detail memory will often see someone at a distance and offer a “best guess” as to their identity. As the person moves closer, the “best guess” offered by the brain may be true or false. Emotional memory works the same way, looking at a current situation/experience and offering a “best guess” by remembering a previous emotional situation. This is the reality of Post-Traumatic Stress Disorder (PTSD) and emotional trauma. We may emotionally relive a combat memory when we hear a car backfire or emotionally feel as if we are being assaulted if someone jokingly grabs us from behind.

It is hoped that this article will explain how emotional memory works and how it can be managed for those who are haunted by the experiences of their past.


Transsexual differences caught on brain scan

Differences in the brain’s white matter that clash with a person’s genetic sex may hold the key to identifying transsexual people before puberty. Doctors could use this information to make a case for delaying puberty to improve the success of a sex change later.

Medics are keen to find concrete physical evidence to help those children who feel they are trapped in the body of the opposite sex. One key brain region involved is the BSTc, an area of grey matter. But the region is too small to scan in a living person so differences have only been picked up at post-mortem.

Antonio Guillamon‘s team at the National University of Distance Education in Madrid, Spain, think they have found a better way to spot a transsexual brain. In a study due to be published next month, the team ran MRI scans on the brains of 18 female-to-male transsexual people who’d had no treatment and compared them with those of 24 males and 19 females.

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They found significant differences between male and female brains in four regions of white matter – and the female-to-male transsexual people had white matter in these regions that resembled a male brain (Journal of Psychiatric Research, DOI&colon 10.1016/j.jpsychires.2010.05.006). “It’s the first time it has been shown that the brains of female-to-male transsexual people are masculinised,” Guillamon says.

In a separate study, the team used the same technique to compare white matter in 18 male-to-female transsexual people with that in 19 males and 19 females. Surprisingly, in each transsexual person’s brain the structure of the white matter in the four regions was halfway between that of the males and females (Journal of Psychiatric Research, DOI&colon 10.1016/j.jpsychires.2010.11.007). “Their brains are not completely masculinised and not completely feminised, but they still feel female,” says Guillamon.

Guillamon isn’t sure whether the four regions are at all associated with notions of gender, but Ivanka Savic-Berglund at the Karolinska Institute in Stockholm, Sweden, thinks they might be. One of the four regions – the superior longitudinal fascicle – is particularly interesting, she says. “It connects the parietal lobe [involved in sensory processing] and frontal lobe [involved in planning movement] and may have implications in body perception.”

A 2010 study of 121 transgender people found that 38 per cent realised they had gender variance by age 5. White matter differences could provide independent confirmation that such children might benefit from treatment to delay puberty.

A study by Sean Deoni‘s team at King’s College London suggests it may soon be possible to look for these differences in such children. Deoni’s team adapted an MRI scanner to be as quiet as possible so it could be used to monitor the development of white matter in sleeping infants. Using new image analysis software they could track when and where myelin – the neuron covering that makes white matter white – was laid down (Journal of Neuroscience, vol 31, p 784). Although the sample was too small to identify any gender differences in development, Deoni expects to see differences developing in the brain “by 2 or 3 years of age”.

Guillamon thinks such scans may not help in all cases. “Research has shown that white matter matures during the first 20 to 30 years of life,” he says. “People may experience early or late onset of transsexuality and we don’t know what causes this difference.”


You say your primary motivation in writing this book is to inspire compassion through scientific understanding. Can you explain the linkage?

There's a much stronger link than people think. It’s about asking ourselves what does it mean to be a good scientist? Too often we think science is a methodology, a process. Our idea is that it's a way of being that enables you to step into uncertainty. And celebrating doubt, stepping into uncertainty, is fundamental to being compassionate.

It's not so much that I'm doing research into compassion. I'm hoping that compassion comes out of the research, by making people part of the process of understanding their own perceptions. Perception underpins everything we think, do, believe, know, or love. Once you understand that, there are consequences like compassion, respect, creativity, choice, community.


New study suggests we have 6,200 thoughts every day

A new study from psychologists at Queen's University in Kingston, Ontario reports observations of the transition from one thought to another in fMRI brain scans. Though the researchers didn't detect the content of our thoughts, their method allowed them to count each one. Referred to as "thought worms," the team says that the average human has 6,200 thoughts per day.

"What we call 'thought worms' are adjacent points in a simplified representation of activity patterns in the brain," said senior study author Jordan Poppenk. "The brain occupies a different point in this 'state space' at every moment. When a person moves onto a new thought, they create a new thought worm that we can detect with our methods."

The study was recently published in the journal Nature Communications.

Not so much the 'what' as the 'when'

There's been a fair amount of research devoted to understanding what a person is thinking based on observations of brain activity. However, the only way to know what a particular pattern of brain activity means would be to recognize its similarity to a brain-activity template known to represent that type of thought. Few such templates are available thus far, and they're time-consuming and expensive to produce.

Poppenk and his MA student Julie Tseng went another way. "We had our breakthrough by giving up on trying to understand what a person is thinking about, and instead focusing on when they have moved on," said Poppenk. He adds, "Our methods help us detect when a person is thinking something new, without regard to what the new thought is. You could say that we've skipped over vocabulary in an effort to understand the punctuation of the language of the mind."

A thought, says the study, is generally viewed by researchers as a mental state, a "transient cognitive or emotional state of the organism." Poppenk says that since such states are relatively stable in terms of brain activity — sustained attention being most closely associated with the angular gyrus — it's possible to identify transitions between one state and another using fMRI data from individual participants. "We argue that neural meta-state transitions can serve as an implicit biological marker of new thoughts," the study reads.

The researchers verified their hypothesis using fMRI scans from two groups of participants: some who were watching movies, and others who were in a resting state. "Transitions detected by our methods predict narrative events, are similar across task and rest, and are correlated with activation of regions associated with spontaneous thought."

"Being able to measure the onset of new thoughts gives us a way," explains Poppenk, "to peek into the 'black box' of the resting mind — to explore the timing and pace of thoughts when a person is just daydreaming about dinner and otherwise keeping to themselves."

The use of fMRIs is key, he adds. "Thought transitions have been elusive throughout the history of research on thought, which has often relied on volunteers describing their own thoughts, a method that can be notoriously unreliable."

Spontaneous thought and attention regions distinguish transitions from meta-stability

Have you thought your 6,200 thoughts yet today?

While we average 6,200 thought worms a day, Poppenk anticipates further research tracking the manner in which the number of daily thoughts an individual has may change over the course of a lifetime. Likewise, he's interested in investigating potential associations between how quickly a person jumps from one thought to another and other mental and personality traits. "For example," he says, "how does mentation rate — the rate at which thought transitions occur — relate to a person's ability to pay attention for a long period?"

In addition, the researcher wonders if "measures of thought dynamics serve a clinical function? For example, our methods could possibly support early detection of disordered thought in schizophrenia, or rapid thought in ADHD or mania."

"We think the methods offer a lot of potential," Poppenk says. "We hope to make heavy use of them in our upcoming work."


Here's What Happens to Your Brain When You Die

You might picture yourself walking through a field, or surrounded by loved ones. Or perhaps making your way down a long, dark tunnel, towards a brilliant, beckoning light.

When the end comes, what you experience will be a veiled secret known only to you – but whatever it is, scientists say those closing moments of consciousness could be powered by something amazing and mysterious taking place inside your brain.

In 2013, researchers at the University of Michigan found that after clinical death occurred in rats, their brain activity actually flared, revealing electrical signatures of consciousness that exceeded levels found in the animals' waking state.

"We reasoned that if near-death experience stems from brain activity, neural correlates of consciousness should be identifiable in humans or animals even after the cessation of cerebral blood flow," said one of the team, neurologist Jimo Borjigin.

And that's exactly what they detected, with anaesthetised rats displaying a surge of highly synchronised brain activity within 30 seconds of an induced cardiac arrest, consistent with patterns you'd see in a highly aroused brain.

The phenomenon detected was a revelation, to the extent it may disprove the notion that just because blood flow has ceased as a result of clinical death, the brain must necessarily be rendered simultaneously inert.

"This study tells us that reduction of oxygen or both oxygen and glucose during cardiac arrest can stimulate brain activity that is characteristic of conscious processing," said Borjigin.

"It also provides the first scientific framework for the near-death experiences reported by many cardiac arrest survivors."

Of course, while the findings do establish a new framework for interpreting where near-death experiences might come from, it doesn't necessarily follow that humans would undergo the same cognitive flare as rats journeying beyond the veil.

But if our brains somehow surge in the same way, it could help to explain the sense of awareness reported by many people who are successfully resuscitated in medical emergencies.

Somebody who knows a bit about that is critical care researcher Sam Parnia from Stony Brook University, who in 2014 released the world's largest study examining near-death experiences and out-of-body experiences.

From interviews with more than 100 survivors of cardiac arrest, 46 percent retained memories of their brush with death, centred around a number of common themes, including bright lights, family, and fear.

But even more intriguingly, two of the patients were able to recall events related to their resuscitation that happened after they had died, which, according to conventional views about consciousness beyond clinical death, shouldn't have been possible.

"We know the brain can't function when the heart has stopped beating, but in this case conscious awareness appears to have continued for up to three minutes into the period when the heart wasn't beating," Parnia told The National Post, "even though the brain typically shuts down within 20 to 30 seconds after the heart has stopped."

It sounds amazing, but it's worth noting that the phenomenon was only reported by 2 percent of patients, and Parnia himself even later admitted "the easiest explanation is that this is probably an illusion".

That 'illusion' could be borne out of a neurological response to physiological stress during cardiac events. In other words, a cognitive experience preceding – not following – the clinical death itself, and which is later remembered by the patient.

Certainly, that's what many in the neuroscience community tend to think.

"Look, I'm sceptical," neurologist Cameron Shaw from Deakin University in Australia told Vice earlier in the year.

"I think out-of-body experiences have been debunked, just because the mechanisms that produce sight and record memories are inoperative."

According to Cameron, because the brain's blood supply is pumped from underneath, the brain would die from the top downwards.

"Our sense of self, our sense of humour, our ability to think ahead – that stuff all goes within the first 10 to 20 seconds," Julian Morgans reported for Vice.

"Then, as the wave of blood-starved brain cells spread out, our memories and language centres short out, until we're left with just a core."

Not a very encouraging outlook, but it's worth noting that it also doesn't accord with the experience of rats – and scientists are still finding evidence of surprising biological processes that continue to thrive even days after death stakes its claim.

All up, we're out of answers, and while science has given us some fascinating insights into what the brain's final moments might be, the research isn't yet conclusive.

As we've said once before, when the curtain is drawn, we really have no firm idea of what it's going to look or feel like. But we know for sure we're all eventually going to find out.


Study shows stronger brain activity after writing on paper than on tablet or smartphone

A study of Japanese university students and recent graduates has revealed that writing on physical paper can lead to more brain activity when remembering the information an hour later. Researchers say that the unique, complex, spatial and tactile information associated with writing by hand on physical paper is likely what leads to improved memory.

"Actually, paper is more advanced and useful compared to electronic documents because paper contains more one-of-a-kind information for stronger memory recall," said Professor Kuniyoshi L. Sakai, a neuroscientist at the University of Tokyo and corresponding author of the research recently published in Frontiers in Behavioral Neuroscience. The research was completed with collaborators from the NTT Data Institute of Management Consulting.

Contrary to the popular belief that digital tools increase efficiency, volunteers who used paper completed the note-taking task about 25% faster than those who used digital tablets or smartphones.

Although volunteers wrote by hand both with pen and paper or stylus and digital tablet, researchers say paper notebooks contain more complex spatial information than digital paper. Physical paper allows for tangible permanence, irregular strokes, and uneven shape, like folded corners. In contrast, digital paper is uniform, has no fixed position when scrolling, and disappears when you close the app.

"Our take-home message is to use paper notebooks for information we need to learn or memorize," said Sakai.

In the study, a total of 48 volunteers read a fictional conversation between characters discussing their plans for two months in the near future, including 14 different class times, assignment due dates and personal appointments. Researchers performed pre-test analyses to ensure that the volunteers, all 18-29 years old and recruited from university campuses or NTT offices, were equally sorted into three groups based on memory skills, personal preference for digital or analog methods, gender, age and other aspects.

Volunteers then recorded the fictional schedule using a paper datebook and pen, a calendar app on a digital tablet and a stylus, or a calendar app on a large smartphone and a touch-screen keyboard. There was no time limit and volunteers were asked to record the fictional events in the same way as they would for their real-life schedules, without spending extra time to memorize the schedule.

After one hour, including a break and an interference task to distract them from thinking about the calendar, volunteers answered a range of simple (When is the assignment due?) and complex (Which is the earlier due date for the assignments?) multiple choice questions to test their memory of the schedule. While they completed the test, volunteers were inside a magnetic resonance imaging (MRI) scanner, which measures blood flow around the brain. This is a technique called functional MRI (fMRI), and increased blood flow observed in a specific region of the brain is a sign of increased neuronal activity in that area.

Participants who used a paper datebook filled in the calendar within about 11 minutes. Tablet users took 14 minutes and smartphone users took about 16 minutes. Volunteers who used analog methods in their personal life were just as slow at using the devices as volunteers who regularly use digital tools, so researchers are confident that the difference in speed was related to memorization or associated encoding in the brain, not just differences in the habitual use of the tools.

Volunteers who used analog methods scored better than other volunteers only on simple test questions. However, researchers say that the brain activation data revealed significant differences.

Volunteers who used paper had more brain activity in areas associated with language, imaginary visualization, and in the hippocampus -- an area known to be important for memory and navigation. Researchers say that the activation of the hippocampus indicates that analog methods contain richer spatial details that can be recalled and navigated in the mind's eye.

"Digital tools have uniform scrolling up and down and standardized arrangement of text and picture size, like on a webpage. But if you remember a physical textbook printed on paper, you can close your eyes and visualize the photo one-third of the way down on the left-side page, as well as the notes you added in the bottom margin," Sakai explained.

Researchers say that personalizing digital documents by highlighting, underlining, circling, drawing arrows, handwriting color-coded notes in the margins, adding virtual sticky notes, or other types of unique mark-ups can mimic analog-style spatial enrichment that may enhance memory.

Although they have no data from younger volunteers, researchers suspect that the difference in brain activation between analog and digital methods is likely to be stronger in younger people.

"High school students' brains are still developing and are so much more sensitive than adult brains," said Sakai.

Although the current research focused on learning and memorization, the researchers encourage using paper for creative pursuits as well.

"It is reasonable that one's creativity will likely become more fruitful if prior knowledge is stored with stronger learning and more precisely retrieved from memory. For art, composing music, or other creative works, I would emphasize the use of paper instead of digital methods," said Sakai.


Why are memories attached to emotions so strong?

Memories linked with strong emotions often become seared in the brain.

Most people can remember where they were on 9/11, or what the weather was like on the day their first child was born. Memories about world events on Sept 10, or lunch last Tuesday, have long been erased.

Why are memories attached to emotions so strong?

"It makes sense we don't remember everything," says René Hen, PhD, professor of psychiatry and neuroscience at Columbia University Vagelos College of Physicians and Surgeons. "We have limited brain power. We only need to remember what's important for our future wellbeing."

Fear, in this context, is not just a momentary feeling but a learning experience critical to our survival. When a new situation makes us fearful, the brain records the details in our neurons to help us avoid similar situations in the future, or use appropriate caution.

What's still a mystery is why these memories, recorded by the brain's hippocampus, become so strong.

To find out, Hen and Jessica Jimenez, an MD/PhD student at Columbia, placed mice into new, frightening environments and recorded the activity of hippocampal neurons that reach out to the brain's fear center (the amygdala). The neurons' activity was also recorded a day later when the mice tried to retrieve memories of the experience.

Unsurprisingly, neurons that respond to the frightening environment send that information to the brain's fear center.

"What was surprising was that these neurons were synchronized when the mouse later recalled the memory," Hen says.

"We saw that it's the synchrony that is critical to establish the fear memory, and the greater the synchrony, the stronger the memory," Jimenez adds. "These are the types of mechanisms that explain why you remember salient events."

How and when synchronization occurs is still unknown, but the answer could reveal the inner workings of the brain that create lifelong memories and lead to new treatments for posttraumatic stress disorder.

"In people with PTSD, many similar events remind them of the original frightening situation," Hen says, "and it's possible that synchronization of their neurons has become too strong."

"We're really trying to dig into the mechanisms of how emotional memories form to find better treatments for people with PTSD and memory disorders in general."


Abstract

To enable the impact of neuroscientific insights on our daily lives, careful translation of research findings is required. However, neuroscientific terminology and common-sense concepts are often hard to square. For example, when neuroscientists study lying to allow the use of brain scans for lie-detection purposes, the concept of lying in the scientific case differs considerably from the concept in court. Furthermore, lying and other cognitive concepts are used unsystematically and have an indirect and divergent mapping onto brain activity. Therefore, scientific findings cannot inform our practical concerns in a straightforward way. How then can neuroscience ultimately help determine if a defendant is legally responsible, or help someone understand their addiction better? Since the above-mentioned problems provide serious obstacles to move from science to common-sense, we call this the 'translation problem'. Here, we describe three promising approaches for neuroscience to face this translation problem. First, neuroscience could propose new ɿolk-neuroscience' concepts, beyond the traditional folk-psychological array, which might inform and alter our phenomenology. Second, neuroscience can modify our current array of common-sense concepts by refining and validating scientific concepts. Third, neuroscience can change our views on the application criteria of concepts such as responsibility and consciousness. We believe that these strategies to deal with the translation problem should guide the practice of neuroscientific research to be able to contribute to our day-to-day life more effectively.


This Is What Sugar Does To Your Brain

We know that too much sugar is bad for our waistlines and our heart health, but now there's mounting evidence that high levels of sugar consumption can also have a negative effect on brain health -- from cognitive function to psychological wellbeing.

While sugar is nothing to be too concerned about in small quantities, most of us are simply eating too much of it. The sweet stuff -- which also goes by names like glucose, fructose, honey and corn syrup -- is found in 74 percent of packaged foods in our supermarkets. And while the Word Health Organization recommends that only 5 percent of daily caloric intake come from sugar, the typical American diet is comprised of 13 percent calories from sugar.

It's easy to see how we can get hooked on sugar. However, we should be aware of the risks that a high-sugar diet poses for brain function and mental well-being.

Here's what you need to know about how overconsumption of sugar could wreak havoc on your brain.

It creates a vicious cycle of intense cravings.

When a person consumes sugar, just like any food, it activates the tongue's taste receptors. Then, signals are sent to the brain, lighting up reward pathways and causing a surge of feel-good hormones, like dopamine, to be released. Sugar "hijacks the brain’s reward pathway," neuroscientist Jordan Gaines Lewis explained. And while stimulating the brain's reward system with a piece of chocolate now and then is pleasurable and probably harmless, when the reward system is activated too much and too frequently, we start to run into problems.

"Over-activating this reward system kickstarts a series of unfortunate events -- loss of control, craving, and increased tolerance to sugar," neuroscientist Nicole Avena explained in a TED-Ed video.

In fact, research has shown that the brains of obese children actually light up differently when they taste sugar, reflecting an elevated "food reward" response. This suggests that their brain circuitry may predispose these children to a lifetime of intense sugar cravings.

It impairs memory and learning skills.

A 2012 study on rats, conducted by researchers at UCLA, found that a diet high in fructose (that's just another word for sugar) hinders learning and memory by literally slowing down the brain. The researchers found that rats who over-consumed fructose had damaged synaptic activity in the brain, meaning that communication among brain cells was impaired.

Heavy sugar intake caused the rats to develop a resistance to insulin -- a hormone that controls blood sugar levels and also regulates the function of brain cells. Insulin strengthens the synaptic connections between brain cells, helping them to communicate better and thereby form stronger memories. So when insulin levels in the brain are lowered as the result of excess sugar consumption, cognition can be impaired.

"Insulin is important in the body for controlling blood sugar, but it may play a different role in the brain," Dr. Fernando Gomez-Pinilla, the study's lead author, said in a statement. "Our study shows that a high-fructose diet harms the brain as well as the body. This is something new."

It may cause or contribute to depression and anxiety.

If you've ever experienced a sugar crash, then you know that sudden peaks and drops in blood sugar levels can cause you to experience symptoms like irritability, mood swings, brain fog and fatigue. That's because eating a sugar-laden donut or drinking a soda causes blood sugar levels to spike upon consumption and then plummet. When your blood sugar inevitably dips back down (hence the "crash"), you may find yourself feeling anxious, moody or depressed.

Sugar-rich and carb-laden foods can also mess with the neurotransmitters that help keep our moods stable. Consuming sugar stimulates the release of the mood-boosting neurotransmitter serotonin. Constantly over-activating these serotonin pathways can deplete our limited supplies of the neurotransmitter, which can contribute to symptoms of depression, according to Dr. Datis Kharrazian, functional medicine expert and author of Why Isn't My Brain Working?.

Chronically high blood sugar levels have also been linked to inflammation in the brain. And as some research has suggested, neuroinflammation may be one possible cause of depression.

Teenagers may be particularly vulnerable to the effects of sugar on mood. A recent study on adolescent mice, conducted by researchers at Emory University School of Medicine, found a diet high in sugar to contribute to depression and anxiety-like behavior.

Research has also found that people who eat a standard American diet that's high in processed foods -- which typically contain high amounts of saturated fat, sugar and salt -- are at an increased risk for developing depression, compared to those who eat a whole foods diet that's lower in sugar.

It's a risk factor for age-related cognitive decline and dementia.

A growing body of research suggests that a sugar-heavy diet could increase risk for developing Alzheimer's disease. A 2013 study found that insulin resistance and blood glucose levels -- which are hallmarks of diabetes -- are linked with a greater risk for developing neurodegenerative disorders like Alzheimer's. The research “offers more evidence that the brain is a target organ for damage by high blood sugar,” endocrinologist Dr. Medha Munshi told the New York Times.

Some researchers, in fact, have even referred to Alzheimer's as "Type 3 Diabetes" -- which suggests that diet may have some role in an individual's risk for developing the disease.

These recognizable-anywhere cans are bad news: They contain 23.5 ounces, nearly three times the suggested serving size for the tea inside. With 90 calories per 8 ounces, finishing an entire can adds up to almost 270.


Watch the video: Unikátní test vašeho mozku a vašich smyslů (January 2022).