On the Mind: by Sandra Eriksson Barman

It is believed that only 10-20% of our genes are active in any cell. For example, the gene for eye color only expresses in the eyes, not the liver, skin or brain. Every cell in the body has the same genetic information; what makes cells, tissues and organs different is that different sets of genes are turned on or expressed. Epigenetics is the study of the ‘marks’ on the genome that determine what genes are expressed. (These marks can be affected by the environment, see the previous post)

Children inherit two copies of a gene, one from each parent. In classic genetics both copies actively shape how the child develops. But an epigenetic form of gene regulation called imprinting, discovered only a few decades ago, can result in the copy of a gene inherited from either the mother or the father being ‘turned off’.

It’s estimated that imprinted genes comprise about 1 percent of the human genome. One gene that has recently been shown to be imprinted, called KCNK9, is predominantly expressed in the cerebellum of the brain and may be involved in bipolar disorder and epilepsy.

Studies of imprinting in the brain of mice by Gregg et. al. have shown that which genes are imprinted can vary both among brain regions and between sexes. So a given gene can be imprinted in the cortex but not in the hypothalamus or vice versa.  And a gene inherited from the father can be silenced in male but not female offspring, or vice versa. While analyzing both embryonic and adult mouse brains, they also found that there is a preferential expression of maternal genes in the developing brain and the opposite — a major paternal contribution — in the adult brain of mice. Even though the mechanisms of imprinting might be similar in humans and mice, humans probably have fewer imprinted genes, and the genes that are imprinted in humans differs from the genes that are imprinted in mice.

Read more here, here, here and here

It was previously thought that we were born with a fixed genetic blueprint and there was nothing we could do to influence that set of plans. Epigenetics tells us a different story. We can, in fact, influence how our genes behave. It’s true the genes we were born with are fixed. But as a waypoint between our genetic information and our environment, there is the epigenome.

The patterns of gene expression are governed by the cellular material — the epigenome — that sits on top of the genes. It is these epigenetic ‘marks’ that tell our genes to switch on or off, to speak loudly or whisper. Through epigenetic marks environmental factors like diet, stress, toxic chemichals and prenatal nutrition can make an imprint on genes that is passed from one generation to the next.

In 1986 the Lancet published the first of two groundbreaking papers showing that if a pregnant woman ate poorly, her child would be at significantly higher than average risk for cardiovascular disease as an adult. Research published over the past 10 years or so suggests that traumatic experiences of a pregnant woman can be transmitted to her unborn children by epigenetic mechanisms and alter the stress response in her offspring.

These epigenetic effects can be sex-specific. In Överkalix, an isolated community in Northern Sweden, birth and death records are remarkably detailed. Research here by Lars Olov Bygren has shown that famine at critical times in people’s lives could affect the life expectancy of those peoples’ grandchildren. But paternal grandfather’s food supply was only linked to the mortality of grandsons, while paternal grandmother’s food supply was only associated with the granddaughters’ mortality.

Read more here, here, here and here

For thousands of years, human beings have looked down on their emotions. This bias against feeling has led people to assume that reason is always best. But what if this is all backwards? What if our emotions know more than we know? What if our feelings are smarter than us?

While there is an extensive literature on the potential wisdom of human emotion, it’s only in the last few years that researchers have demonstrated that the emotional system might excel at complex decisions, or those involving lots of variables. This is largely because the unconscious is able to handle a surfeit of information, digesting the facts without getting overwhelmed. (Human reason, in contrast, has a very strict bottleneck and can only process about four bits of data at any given moment.)

But this raises the obvious question: how do we gain access to all this analysis, which by definition is taking place outside of conscious awareness? Here’s where emotions come in handy. Every feeling is like a summary of data, a quick encapsulation of all the information processing that we don’t have conscious access to.

In a new paper, published in Emotion by scientists then at Cornell University, provided a test of the possible advantages of using our emotions to make complex decisions.  While consciously focusing on feelings versus details, participants made choices that varied in complexity. The detail-focused group excelled at making simple decisions. Thinking in a rational manner made them nearly 20 percent more effective at identifying the best car alternative when there were only sixteen total pieces of information. However, those focused on feelings proved far better at finding the best car in a more complex condition. While deliberate thinkers barely beat random chance, those listening to their feelings identified the ideal option nearly 70 percent of the time. See also these papers On making the right choice and Feeling the future.

From this and this post at the Frontal Cortex blog.

The body evolved under conditions of frequent movement. Therefore it’s not surprising that exercise is necessary for maintaining health. Even so, the effects of exercise on the brain and mental functioning are still somewhat unknown. New research shows that exercise targets many aspects of brain function and has broad effects on overall brain health.

Studies have shown that exercise has antidepressant properties and that exercise can improve the brain functioning of the elderly and may even protect against dementia. Some studies have found that exercise boosts activity in the brain’s frontal lobes — associated with reasoning, planning, emotions, and problem solving — and the hippocampus — associated with learning, memory and emotional regulation. We don’t really know how or why this occurs. Animal studies have also found that exercise increases levels of serotonin, dopamine and norepinephrine (many antidepressant drugs, including Prozac, are designed to raise the concentration of those molecules in the brain).

Exercise has also been found to increase levels of “brain-derived neurotrophic factor” (BDNF), a growth factor associated with learning and memory. BDNF’s primary role seems to be to help brain cells survive longer, so this may explain some of the beneficial effects of exercise on dementia. Overall, BDNF improves the function of neurons, encourages their growth, and strengthens and protects them against the natural process of cell death.

Read more here and here

And here some of the more well-known beneficial effects of exercise on the body:

1. Moderate exercise has a beneficial effect on the human immune system.
2. Exercise generally improves sleep for most people, and helps sleep disorders such as insomnia.
3. Longer-term effects as the body adapts to regular exercise includes your heart getting larger, bones becoming denser and the vital capacity of your breath deepening. Increased amount of oxygen is delivered to, and carbon dioxide removed from, the body (including the brain).
4. The increased flow of blood helps the removal of metabolic wastes.
5. Increased ability of exercising muscles to consume oxygen, lowered resting and exercise heart rates, reduced bone-mineral loss, decreased blood pressure, and increased efficiency of the heart.
6. Increased levels of HDL-C (“good cholesterol”). Risk of heart disease, stroke and several types of cancer also seem be reduced with regular physical activity.

Sources:1,2,3,4,5 and 6

Subjects in this study practiced mindfulness meditation training for 8 weeks, about 30 minutes a day, with a meditation technique that focuses on nonjudgmental awareness of sensations and feelings. Brain images were taken of each subject before and after the training. Increases in gray-matter density were found in the hippocampus —an area responsible for learning, memory and emotional regulation. Several conditions such as major depression and post-traumatic stress disorder are associated with decreased density or volume of the hippocampus. Changes were also seen in other structures, associated with the conscious experience of the self, social cognition and regulation of emotion and cognition. 

Although no change was seen in a self-awareness-associated structure called the insula, which had been identified in earlier studies of experienced meditators, the authors suggest that longer-term meditation practice might be needed to produce changes in that area.

“It is fascinating to see the brain’s plasticity and that, by practicing meditation, we can play an active role in changing the brain and can increase our well-being and quality of life.” says Britta Hölzel, one of the authors of the paper.

Read more

Stimulating part of the brain with a gentle electrical current helps us discard our preconceptions and think outside the box.

In a new study by Allan W. Snyder and Richard P. Chi, students who received electrical stimulation of the brain’s anterior temporal lobes — situated right in front of the ears — were more likely to be able to figure out an unfamiliar puzzle than those who did not get zapped. Three times as many students solved the puzzles within a time limit when the electrical current was applied from the right side of the brain to the left side, causing increased activity on the right side and decreased activity on the left side of the brain (the right side of the brain is connected to the left side of the body and vice versa).

‘Our perceptions, memory, and decisions are based on  filtered information. We view the world top down though concepts or mental  templates which are built up from our past experience. These concepts are crucially important to our survival. They enable us to make rapid predictions about what is most likely, based on only partial information.  

‘But, this strategy leaves us susceptible to certain kinds of perceptual and  cognitive errors - from visual illusions to false memories and prejudice - and  it makes us inclined to connect the dots in ways that are familiar, rather than  to explore novel interpretations. In other words our observations of the world are strongly shaped by our preconceptions. Our experiences can blind us.

‘Our findings are consistent with the theory that inhibition to the left  anterior temporal lobe can lead to a cognitive style that is less influenced by  mental templates and that the right anterior temporal lobe may be associated  with insight or novel meaning’, says Snyder.

From this and this article.

The bowels of every baby are filled with trillions of bacteria that outnumber the cells of our own body by ten to one. This “microbiome” acts like one of our own organs, harvesting energy from our food and blocking the growth of harmful bacteria. It’s also a gift from our mothers. In the womb, we’re largely sterile. It’s only when we pass through the vagina that we’re seeded with our first set of bacteria.

By studying mice, Rochellys Diaz Heijtz from the Karolinska Institute has found that a mammal’s gut bacteria can affect the way its brain develops as it grows up. They could even influence how it behaves as an adult. Heijtz worked with two strains of mice – one that was completely free of germs, and another that had an intact microbiome but no disease-causing bacteria. The two strains behaved differently. The germ-free mice were more active, and spent more time scurrying around their enclosures. They were also less anxious and more likely to take risks, such as spending long periods of time in bright light or open spaces.

The absence of the gut bacteria also triggered a slew of changes in the rodents’ brains. Heijtz compared her germ-free and disease-free mice and found that over a hundred genes were twice as active in the brains of one strain compared to the other.

A Japanese team has found that gut bacteria can change levels of stress hormones in the body. And an American group has found that germ-free mice have almost three times more serotonin in their blood than normal ones. Heijtz herself found that chemicals like noradernaline and dopamine came and went at a faster pace in the germ-free mice. All of these chemicals could affect the way the young brain develops.

“We know that animals in ‘germ-free’ conditions can reproduce, they have a longer lifespan, and they seem to live perfectly OK, provided you don’t expose them to stress or damage,” said Sven Pettersson, the Karolinska Institute microbiologist who, along with Diaz, led the research. “The moment you do that they’re much more fragile.”

From this post by Not exactly rocket science and this article from BBC News

Researchers in this study found that when trying to get a job, find a partner, pass an exam or get through surgery, those who spent more time entertaining positive fantasies did worse. On the other hand those who entertained more negative future fantasies were more likely to achieve their goals.

On the other hand, positive expectations were associated with success. People who had positive expectations did better than those whose expectations were negative.

Expectations are based on past experiences. You expect to do well because you’ve done well before. Fantasies, though, involve imagining something you hope will happen in the future. The problem with positive fantasies is that they allow us to anticipate success in the here and now. However they don’t alert us to the problems we are likely to face along the way and can leave us with less motivation—after all it feels like we’ve already reached our goal.

From this post by PsyBlog

Emotions influence how we process and pay attention to information, and different kinds of cognitive tasks benefit from different moods. Sadness seems to bolster our attention and make us more analytical, while happiness promotes a more freewheeling kind of information processing which leads to more creative insights.

According to Mark Jung Beeman and John Kouios, two scientists who have studied the neuroscience of aha moments, the brain is more likely to solve insights when the mind is relaxed, happy and perhaps a little distracted. They’ve found, for instance, that subjects in a positive mood solve approximately 20 percent more insight problems than control subjects. And in a series of recent studies they have imaged people’s brains as they prepare to tackle a puzzle but before they’ve seen it, finding that those whose brains show a particular signature of preparatory activity, one that is strongly correlated with positive moods, turn out to be more likely to solve the puzzles with sudden insight than with trial and error (the clues can be solved either way).

So why does happiness and relaxation make us better at solving remote associate problems? Beeman and Kounios describe the insight process as a delicate mental balancing act. At first, the brain needs to control itself, which is why areas involved with executive control, like the prefrontal cortex and anterior cingulate, are activated. The scare resource of attention is lavished on a single problem. But then, once the brain is sufficiently focused, the cortex needs to relax, to seek out the more remote associations that will provide the insight. “What we think is happening,” sais Beeman, “is that the humor, this positive mood lowers the brain’s threshold for detecting weaker or more remote connections.”

And that’s why relaxation and happiness are so helpful: these moods make us more likely to direct the spotlight of attention inwards, so that we become better able to eavesdrop on the quiet yet innovative thoughts we often overlook. (That’s why so many of my best ideas often come during warm showers.) In contrast, when people are diligently focused (and perhaps a little melancholy), their attention tends to be directed outwards, towards the details of the problem they’re trying to solve. While this pattern of attention is necessary when solving problems analytically, it actually prevents us from detecting those unlikely connections that lead to insights and epiphanies.

From this and this article