miércoles, 31 de marzo de 2010

Brain Waves and Meditation

Brain Waves and Meditation

Scientists use a special cap to measure brain waves during meditation. (Credit: Image courtesy of NTNU)ScienceDaily (Mar. 31, 2010) — Forget about crystals and candles, and about sitting and breathing in awkward ways. Meditation research explores how the brain works when we refrain from concentration, rumination and intentional thinking. Electrical brain waves suggest that mental activity during meditation is wakeful and relaxed.

"Given the popularity and effectiveness of meditation as a means of alleviating stress and maintaining good health, there is a pressing need for a rigorous investigation of how it affects brain function," says Professor Jim Lagopoulos of Sydney University, Australia. Lagopoulos is the principal investigator of a joint study between his university and researchers from the Norwegian University of Science and Technology (NTNU) on changes in electrical brain activity during nondirective meditation.

Constant brain waves

Whether we are mentally active, resting or asleep, the brain always has some level of electrical activity. The study monitored the frequency and location of electrical brain waves through the use of EEG (electroencephalography). EEG electrodes were placed in standard locations of the scalp using a custom-made hat

Participants were experienced practitioners of Acem Meditation, a nondirective method developed in Norway. They were asked to rest, eyes closed, for 20 minutes, and to meditate for another 20 minutes, in random order. The abundance and location of slow to fast electrical brain waves (delta, theta, alpha, beta) provide a good indication of brain activity.

Relaxed attention with theta

During meditation, theta waves were most abundant in the frontal and middle parts of the brain.

"These types of waves likely originate from a relaxed attention that monitors our inner experiences. Here lies a significant difference between meditation and relaxing without any specific technique," emphasizes Lagopoulos.

"Previous studies have shown that theta waves indicate deep relaxation and occur more frequently in highly experienced meditation practitioners. The source is probably frontal parts of the brain, which are associated with monitoring of other mental processes."

"When we measure mental calm, these regions signal to lower parts of the brain, inducing the physical relaxation response that occurs during meditation."

Silent experiences with alpha

Alpha waves were more abundant in the posterior parts of the brain during meditation than during simple relaxation. They are characteristic of wakeful rest.

"This wave type has been used as a universal sign of relaxation during meditation and other types of rest," comments Professor Øyvind Ellingsen from NTNU. "The amount of alpha waves increases when the brain relaxes from intentional, goal-oriented tasks.This is a sign of deep relaxation, -- but it does not mean that the mind is void."

Neuroimaging studies by Malia F. Mason and co-workers at Dartmouth College NH suggest that the normal resting state of the brain is a silent current of thoughts, images and memories that is not induced by sensory input or intentional reasoning, but emerges spontaneously "from within."

"Spontaneous wandering of the mind is something you become more aware of and familiar with when you meditate," continues Ellingsen, who is an experienced practitioner. "This default activity of the brain is often underestimated. It probably represents a kind of mental processing that connects various experiences and emotional residues, puts them into perspective and lays them to rest."

Different from sleep

Delta waves are characteristic of sleep. There was little delta during the relaxing and meditative tasks, confirming that nondirective meditation is different from sleep.

Beta waves occur when the brain is working on goal-oriented tasks, such as planning a date or reflecting actively over a particular issue. EEG showed few beta waves during meditation and resting.

"These findings indicate that you step away from problem solving both when relaxing and during meditation," says Ellingsen.

Nondirective versus concentration

Several studies indicate better relaxation and stress management by meditation techniques where you refrain from trying to control the content of the mind.

"These methods are often described as nondirective, because practitioners do not actively pursue a particular experience or state of mind. They cultivate the ability to tolerate the spontaneous wandering of the mind without getting too much involved. Instead of concentrating on getting away from stressful thought and emotions, you simple let them pass in an effortless way."

Take home message

Nondirective meditation yields more marked changes in electrical brain wave activity associated with wakeful, relaxed attention, than just resting without any specific mental technique.


Story Source:

Adapted from materials provided by The Norwegian University of Science and Technology (NTNU), via AlphaGalileo.


Journal Reference:

1.. Lagopoulos et al. Increased Theta and Alpha EEG Activity During Nondirective Meditation. The Journal of Alternative and Complementary Medicine, 2009; 15 (11): 1187 DOI: 10.1089/acm.2009.0113
The Norwegian University of Science and Technology (NTNU) (2010, March 31). Brain waves and meditation. ScienceDaily. Retrieved March 31, 2010, from http://www.sciencedaily.com/releases/2010/03/100319210631.htm
Note: If no author is given, the source is cited instead.

miércoles, 24 de marzo de 2010

Optimism boosts the immune system

Optimism boosts the immune system
March 23rd, 2010 in Medicine & Health / Psychology & Psychiatry

Feeling better about the future might help you feel better for real. In a new study, psychological scientists Suzanne Segerstrom of the University of Kentucky and Sandra Sephton of the University of Louisville studied how law students' expectations about the future affected their immune response. Their conclusions: Optimism may be good for your health.

Other studies have found that people who are optimistic about their health tend to do better. For example, people who are optimistic about heart transplant surgery recover better from that grueling operation. But it's not clear how optimism affects your health — or whether pessimism makes you less healthy.

For this study, reported in Psychological Science, a journal of the Association for Psychological Science, the researchers recruited first-year law students by sending them a packet during the summer before classes started. The 124 students that participated in the research were studied at five times over six months. Each time, they answered questions about how optimistic they felt about law school. Then they were injected with material that should summon an immune response and two days later, they came back to have the injection site measured. A larger bump in the skin means a stronger immune response. Immune systems are many-faceted; this test only measures the strength of the part that is responsible for fighting viral infections and some bacterial infections.

The students' general outlook on life — whether they had an optimistic disposition — didn't account for the differences in immune responses between students. But as each student's expectations about law school waxed and waned, their immune response followed along. At more optimistic times, they'd have bigger immune responses; at a more pessimistic time, a more sluggish immune response. So, being optimistic about success in a specific, important domain may promote better immunity against some infections.

Of course, the law students often have good reason to be optimistic or pessimistic; by a few months into the first semester, they've gotten some grades back and started to figure out if they're good or bad at law school. "I don't think that I would advise people that they should revise their expectations to be unrealistic," says Segerstrom. "But if people have slightly more positive views of the future than is actually true, that's adaptive."

Provided by Association for Psychological Science

viernes, 19 de marzo de 2010

Learning deficits in adolescence linked to novel brain receptor

March 18th, 2010 in Medicine & Health / Research

It is well known that the onset of puberty marks the end of the optimal period for learning language and certain spatial skills, such as computer/video game operation. Recent work published in the journal Science by Sheryl Smith, PhD, professor of physiology and pharmacology, and colleagues at SUNY Downstate Medical Center in Brooklyn shows that a novel brain receptor, alpha4-beta-delta, emerges at puberty in the hippocampus, part of the brain that controls learning and memory.

Before puberty, expression of this receptor is low and learning is optimal. However, at puberty, increases in this receptor reduce brain excitability and impair spatial learning. Dr. Smith has demonstrated that this learning deficit can be reversed by a stress steroid that diminishes the harmful effects of the alpha4-beta-delta receptors, thereby facilitating learning.

"These findings suggest that intrinsic brain mechanisms alter learning during adolescence, but that mild stress may be one factor that can reverse this decline in learning proficiency during the teenage years," says Dr. Smith. "They also suggest that different strategies for learning and motivation may be helpful in middle school. And it is within the realm of possibility that a drug could be developed that would increase learning ability post-puberty, one that might be especially useful for adolescents with learning disabilities."

In 2007, Dr. Smith and colleagues demonstrated that a hormone normally released in response to stress, THP, actually reverses its effect at puberty, when it increases activity of the hippocampus. While in adults this hormone acts like at tranquilizer, in adolescents it has the opposite effect, an action that may help to explain mood swings in teenagers.

The new report on learning deficits published in Science by Dr. Smith and colleagues is titled, "A Critical Role for Alpha4-Beta-Delta GABA-A Receptors in Shaping Learning Deficits at Puberty in Mice."

Provided by SUNY Downstate Medical Center

Extraordinary Perception

March 16, 2010

Extraordinary Perception
We think of people with autism as having a deficit in cognitive processing—but their distractibility could also result from having enhanced perceptual capabilities
By Wray Herbert

When Pulitzer Prize–winning music critic Tim Page was in second grade, he and his classmates went on a field trip to Boston. He later wrote about the experience as a class assignment, and what follows is an excerpt:

“Well, we went to Boston, Massachusetts, through the town of Warrenville, Connecticut, on Route 44A. It was very pretty, and there was a church that reminded me of pictures of Russia from our book that is published by Time-Life. We arrived in Boston at 9:17. At 11 we went on a big tour of Boston on Gray Line 43, made by the Superior Bus Company like School Bus Six, which goes down Hunting Lodge Road where Maria lives and then on to Separatist Road and then to South Eagleville before it comes to our school. We saw lots of good things like the Boston Massacre site. The tour ended at 1:05. Before I knew, it we were going home. We went through Warrenville again, but it was too dark to see much. A few days later it was Easter. We got a cuckoo clock.”

Page received an unsatisfactory grade on his essay. What’s more, his irate teacher scrawled in red across the top of the essay: “See me!” As he recalls in his new memoir Parallel Play (Doubleday, 2009), such incidents were not uncommon in his childhood, and he knew why he was being scolded: “I had noticed the wrong things.”

A Question of Focus
The subtitle of Page’s memoir is Growing Up with Undiagnosed Asperger’s, and indeed Page didn’t learn until age 45 that he suffers from what is called autism spectrum disorder, or ASD. ASD is usually defined by impairments in social interaction and communication, but many people with autism and Asperger’s syndrome (in which symptoms are milder) also tend to fixate on and remember seemingly irrelevant information in their world. Their attention seems to be awry, or to use Page’s words, they notice the wrong things.

But why? What’s going on in the autistic mind that makes the details of bus routes infinitely fascinating? Why are people like Page so easily distracted from the main act? Psychologists at University College London think that it might be a mistake to consider such distractibility as simply a deficit. To the contrary, Anna Remington and John Swettenham and their colleagues speculate that people with ASD might have a greater than normal capacity for perception, so that what appears as irrelevant distraction is really a cognitive bonus. They decided to test the idea in the lab.

Selective Attention
Remington and Swettenham studied a group of people with autism spectrum disorder, most of whom had Asperger’s, along with normal controls. They asked all the subjects to look at a computer screen, which displayed various combinations of letters and dots forming a ring. The subjects were instructed to very rapidly determine if the letters N or X were present in the ring and then hit the corresponding key on the keyboard. Some of the circles—those with more letters—were more difficult to process than others. There were also other letters floating outside the circle, but the subjects were specifically instructed to ignore those letters. Those floating letters were the laboratory equivalent of an irrelevant distraction in the real world.

The psychologists were measuring perceptual capacity—that is why they varied the complexity of the task. As expected, everyone was slower at the task when the ring contained more letters. The researchers were also measuring distractibility. When a letter outside the ring was one of the target letters (N or X), the subjects often took a longer time finding the N or X in the ring—indicating they were distracted by the presence of a target letter in the location that they were supposed to ignore.

The psychologists reasoned that as long as the subjects’ total perceptual capacity was not exhausted, they would also process the irrelevant, distracting letters within their visual field. Once they had surpassed their perceptual capacity—once the ring of letters was sufficiently complex—irrelevant processing would stop. So if ASD subjects in fact have greater processing capacity, then they should process more distracting information even as the main task becomes increasingly complex.

Seeing the Bigger Picture
And that is exactly what they found. As the researchers reported online in the journal Psychological Science, although there was no difference among subjects in either reaction time or accuracy on the main task, those with ASD processed the irrelevant letters while solving much more complex problems. Their reaction times indicated that they were still noticing when the extra letter was an N or X, while also finding the target letter in the ring with the same speed and accuracy as the normal controls. Put another way, they weren’t ignoring the main task, nor were they distracted away from it. Instead they were completing their work and moving on, using their untapped capacity.

But here’s the rub. Although this increased distractibility may be a talent rather than a deficit, the psychologists point out, it nonetheless can have detrimental consequences in real-life situations. Just ask Tim Page about his uncanny facility for bus routes.

Source: Scientific American