Posts Tagged ‘EEG’

The Creative Brain

February 26, 2019

The title of this post is the same as the title of a chapter in Daniel Goleman’s book “The Brain and Emotional Intelligence: New Insights.” The chapter begins,
“‘Right brain good, left brain bad.’ That belief about creativity and the right and left hemispheres of the brain dates back to the Seventies, and reflects a very outdated bit of neuromythology. The new understanding about left and right hemispheres is more specific to the topography of the brain: when it comes to left versus right, do you mean left front, left middle, left rear?”

The right hemisphere has more neural connections both within itself and through the brain. It has strong connections to emotional centers like the amygdala and to subcortical regions throughout the lower parts of the brain. The left side has far fewer connections with itself and beyond to the rest of the brain. The left hemisphere is made of neatly stacked vertical columns, which allow the clear differentiation of separate mental functions, but less integration of those functions. The right hemisphere is more of a mix structurally.

Brain studies on creativity reveal what goes on that “Aha!” moment, when we get a sudden insight. When EEG brain waves are measured during a creative moment, it turns out there is a very high gamma activity that spikes 300 milliseconds before the answer comes to us. This gamma activity indicates the acting together of neurons, as far-found brain cells connect in a new neural network as when a new association emerges. Immediately after that gamma spike, the new idea enters consciousness.

This heightened activity focuses on the temporal area, a center on the side of the right neocortex. This is the same brain area that interprets metaphor and gets jokes. This high gamma spike signals that the brain has a new insight. At that moment, right hemisphere cells are using these longer branches and connections to other parts of the brain. They’ve collected more information and put it together in a novel organization.

In spite of what you might have read or heard, there are two primary modes of creative thinking. The first is to concentrate intently on the goal or problem. The next stage is to let go. During this stage you are relaxing and letting your non conscious brain do its creative thing. This stage is characterized by a high alpha rhythm, which signals mental relaxation, a state of openness, or daydreaming and drifting, where we’re more receptive to new ideas. This sets the stage for novel connections that occur during the gamma spike. Of course, after that “aha moment” you need to return to concentration to evaluate the creative idea and asses how adequately it addresses the problem.

In all but rare cases, this is an iterative process. And this iterative process can occur over the course of years. There are documented cases of mathematicians trying to solve a problem. The problem appears to be intractable, because the “aha” moment never seems to come. But, sometimes it eventually appears seemingly from nowhere.
The name of this process is incubation, because you are not consciously trying to solve the problem. However, your non conscious mind has been working on this problem, perhaps even when you thought you were sleeping.

Goleman concludes the chapter with a final state, implementation. Here’s where a good idea will sink or swim. He remembers talking to the director of a huge research lab. He had about 4,000 scientists and engineers working for him. He told Goleman,”We have a rule about a creative insight: if somebody offers a novel idea, instead of the next person who speaks shooting it down—which happens all to often in organizational life—the next person who speaks must be an angel’s advocate someone who says, ‘that’s a good idea and here’s why.” Goleman writes, “Creative ideas are like a fragile bud—they’ve got to be nurtured so that they can blossom.”

Different creative people use different processes, so there is no optimal way of being creative. Each creative person creates her own creative process, which might even vary from problem to problem.

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It is Good for You to Spend Time in Natural Environments

November 23, 2018

This post is based on a presentation titled “Modulation of Cognitive Restoration Dependent on Time Spent in Natural Environments” by Rachel J. Hopman, Sarah B. Lotemplio, Emily Scott, and David L. Strayer at the 2018 Meeting of the Psychonomic Society.

Attention Restoration Theory says that spending time in natural environments can restore cognitive functioning, decrease stress, and improve cognitive performance. EEG research shows that those who have spent prolonged time in natural environments have decreased theta power (4-8Hz) in the mid frontal regions due to down regulation of the attentional control network, thus restoring neural regions associated with attentional processing. However, research has yet to determine the time course of the restorative experience.

In a series of studies EEG recordings were collected during a resting baseline period from 104 participants before, during, and after a nature trip to determine amount of change in neural activity associated with attentional fatigue. Midfrontal theta power significantly decreased from pre-trip testing each day during the nature exposure and increased each week after the trip. These results show that exposure to natural environments influences attentional processing and that these effects are additive over time.

We’ve Finally Seen How the Sleeping Brain Stores Memories

December 29, 2017

The title of this post is identical to the title of a post by Jessica Hamzelou in the 7 October 2017 issue of the New Scientist. To do this research needed to find volunteers who were able to sleep in an fMRI scanner. They needed to scan 50 people to find the 13 who were able to do so. These volunteers were taught to press a set of keys in a specific sequence. It took each person between 10 to 20 minutes to master this sequence.

Once they learned this sequence they each put on a cap of EEG electrodes to monitor the electrical activity of their brains, and entered an fMRI scanner, which detects which regions of the brain are active.

There was a specific pattern of brain activity when the volunteers performed the key-pressing task. Once they stopped, this pattern kept replaying in their brains as if each person was subconsciously reviewing what they had learned.

The volunteers were then asked to go to sleep, and they were monitored for two and a half hours. At first, the pattern of brain activity continued to replay in the outer region of the brain called the cortex, which is involved in higher thought.

When the volunteers entered non-REM sleep, which is known as the stage when we have relatively mundane dreams, the pattern started to fade in the cortex, but a similar pattern of activity started in the putamen, a region deep within the brain
(eLife, doi.org/cdsz). Shabbat Vahdat, the team leader at Stanford University, said that the memory trace evolved during sleep.

The researchers think that movement-related memories are transferred to deeper brain regions for long-term storage. Christoph Nissen at University Psychiatric Services in Bern Switzerland says, “this chimes with the hypothesis that the brain;’s cortex must free up space so that it can continue to learn new information.

The title of this post is identical to the title of a post by Jessica Hamzelou in the 7 October 2017 issue of the New Scientist. To do this research needed to find volunteers who were able to sleep in an fMRI scanner. They needed to scan 50 people to find the 13 who were able to do so. These volunteers were taught to press a set of keys in a specific sequence. It took each person between 10 to 20 minutes to master this sequence.

Once they learned this sequence they each put on a cap of EEG electrodes to monitor the electrical activity of their brains, and entered an fMRI scanner, which detects which regions of the brain are active.

There was a specific pattern of brain activity when the volunteers performed the key-pressing task. Once they stopped, this pattern kept replaying in their brains as if each person was subconsciously reviewing what they had learned.

The volunteers were then asked to go to sleep, and they were monitored for two and a half hours. At first, the pattern of brain activity continued to replay in the outer region of the brain called the cortex, which is involved in higher thought.

When the volunteers entered non-REM sleep, which is known as the stage when we have relatively mundane dreams, the pattern started to fade in the cortex, but a similar pattern of activity started in the putamen, a region deep within the brain
(eLife, doi.org/cdsz). Shabbat Vahdat, the team leader at Stanford University, said that the memory trace evolved during sleep.

The researchers think that movement-related memories are transferred to deeper brain regions for long-term storage. Christoph Nissen at University Psychiatric Services in Bern Switzerland says, “this chimes with the hypothesis that the brain;’s cortex must free up space so that it can continue to learn new information.

Transforming the Emotional Mind

June 13, 2016

The title of this post is identical to the title of Chapter nine of Sharon Begley’s “Train Your Mind, Change Your Brain.”  In the 1970s, Davidson and his colleagues discovered striking differences in the patterns of brain activity that characterize people at opposite ends of the “eudaemonic scale,” which provides the spectrum of baseline happiness.  There are specific brain states that correlate with happiness.

Secondly, brain-activation patterns can change as a result of therapy and mindfulness meditation, in which people learn to think differently about their thoughts.  This has been shown in patients with obsessive-compulsive disorder and with patients suffering from depression.  Mental training practice and effort can bring about changes in the function of the brain.

Given these two facts Davidson built the hypothesis that meditation or other forms of mental training can, by exploiting the brain’s neuroplasticity, produce changes, most likely in patterns of neuronal activation, but perhaps even in the structure of neural circuitry that underlie enduring happiness and other positive emotions.  Then therapists and even individuals by exploiting the brain’s potential to change its wiring can restore the brain and the mind to emotional health.

In 1992 Davidson and his colleagues found that activity in the brain’s prefrontal cortex, as detected by EEG, is a reflection of a person’s emotional state.  Asymmetric activation in this region corresponds to different “affective styles.”  When activity in the left prefrontal cortex is markedly and chronically higher than in the right, people report feeling alert, energized, enthusiastic, and joyous, enjoying life more and having a greater sense of  well-being.  In other words, they tend to be happier.  When there is greater activity in the right prefrontal cortex, people report feeling negative emotions including worry, anxiety, and sadness.  They express discontent with life and rarely feel elation or joy.  If the asymmetry is so extreme that activity in the right prefrontal cortex swamps that in the left, the person has a high risk of falling into clinical depression.

The Dalai Lama has noted that the most powerful influences on the mind come from within our own mind.  The findings that, in highly experienced  meditators, there is greater activity in the left frontal cortex “imply that happiness is something we can cultivate deliberately through mental training that affects the brain.”

Research has shown that every area of the brain that had been implicated in some aspect of emotion had also been linked to some aspect of thought:  circuitry that crackles with electrical activity  when when the mind feels an emotion and circuitry  that comes alive when the mind undergoes cognitive processing, whether it is remembering, or thinking, or planning, or calculating, are intertwined as yarn on a loom.  Neurons principally associated with thinking connect to those mostly associated with emotion, and vice versa.  This neuroanatomy is consistent with two thousand years of Buddhist thought, which holds that emotion and cognition cannot be separated.

Using fMRI Davidson measured activity in the brain’s amygdala, an area that is active during such afflictive emotions as distress, fear, anger,and anxiety.  Davidson said, “Simply by mental rehearsal of the aspiration that a person in a photo be free of suffering, people can change the strength of the signal in the amygdala.  This signal in he fear-generating amygdala can be modulated with mental training.

Eight Buddhist adepts and eight controls  with 256 electrodes glued to their scalps engaged in the form of meditation called pure compassion, in which the meditator focuses on unlimited compassion and loving-kindness toward all living beings.  This produces a state in which love and compassion permeates the whole mind, with no other considerations, reasoning, or discursive thoughts.  The brain waves that predominated were gamma waves.  Scientists  believe that brain waves of this frequency reflect the activation and recruitment of neural resources and general mental effort.  They are also a signature of neuronal activity that knits together far-found brain circuits.  In 2004 the results of this study were published in the “Proceedings of the National Academy of Sciences.  Not surprisingly the results of the monks were quite pronounced.  But it was encouraging to discover that some of the controls who received a crash crash course and only a week’s worth of compassion meditation, showed a slight but significant increase in the gamma signal.

fMRI images were also taken.  The differences between the adepts and the controls were quite interesting.  There was significantly greater activation in the right ins and caudate, a network that other research has linked to empathy and maternal love.  These differences were most pronounced in monks with more years of meditation.  Connections from the frontal regions to the brain’s emotion regions seemed to become stronger with more years practicing meditation.  It was clear that mental training that engages concentration and thought can alter connections between the thinking brain and the emotional brain.

A surprising finding was that when the monks engaged in compassion meditation, their brains showed increased activity in regions responsible for planned movement.   It appeared that the monks’ brains were itching to go to the aid of those in distress.  Another spot of activation in the brains of the meditating monks jumped out in  an area in the left prefrontal cortex, the site of activity association with happiness.  Activity in the left prefrontal swamped activity in the right prefrontal  to a degree never before seen from purely mental activity.

Davidson concluded, “ I believe that Buddhism has something to teach us as scientists about the possibilities of human transformation and in providing a set of methods and a road map of how to achieve that.  We can have no idea how much plasticity there really is in the human brain until we see what intense mental training, not some weekly meditation session, can accomplish.  We’ve gotten the idea in Western culture, that we can change our mental status by a once-a-week, forty-five intervention, which is completely cockamamy.  Athletes and musicians train many hours every day.  As a neuroscientist, I have to believe that engaging in compassion meditation every day for an hour each day would change your brain in important ways.  To deny that without testing it, to accept the null hypothesis, is simply bad science.”

Davidson continues, “I believe that neuroplasticity will reshape psychology in the coming years.  Much of psychology had accepted the idea of a fixed program unfolding in the brain, one that strongly shapes behavior, personality, and emotional states.  That view is shattered by the discoveries of neuroplasticity.  Neuroplasticity will be the counter to the deterministic view (that genes have behavior on a short leash).  The message I take for my own work is that I have a choice in how I react, that who I am depends on the choices I make, and that who I am is therefore my responsibility.”

The Silent

May 14, 2016

The fifth cryptomind discussed in “The Mind Club” is The Silent.  This chapter is about those we cannot communicate with who, because of trauma to the brain, cannot communicate with us.  The EEG can be used to take measurements.  Disordered conscious states can be diagnosed by the EEG patterns.  An ordering of conscious states follows:

Wakefulness
Locked in syndrome
Minimally conscious
Coma
Vegetative State
Brain Death

It is unfortunate that unless EEG measurements are done along with further diagnosis the Locked in syndrome can be mistaken for a lower level of consciousness.

The term locked-in syndrome was coined by Fred Plume and Jerome Posner.  For many years it was not realized that someone was actually locked-in.  Healthy memory remembers watching a movie when someone asked suppose some is locked inside the unconscious state.  The reply was that that was something too horrible to imagine.  But there are real people who can accomplish some impressive feats.  Jean-Dominique Bauby was an editor who suffered a stroke and found himself locked-in.  But he was able to communicate by blinking his one eye that was functioning.  It took him 200,000 blinks to write the Diving Bell and the Butterfly.  He lived to see the book published, but he died before he saw the enormous success of the book and the beautiful movie  with the same title that was based on the book.

People react and adapt to this locked-in state differently.  Bauby could have continued a productive career had he not died.  But an Englishman, Tony Nicklinson, did not and wanted to commit suicide.  However, being locked-in he could not commit suicide.  He petitioned the court to allow doctors to provide an assisted suicide.  After much deliberation, the courts decline.  However, he did manage to commit suicide by refusing to swallow.

In addition to EEGs, fMRIs can provide very useful information.  The primary problem with fMRI’s is that they are expensive.

To read more about current research on this topic, see some of the healthy memory blog posts by Dehaene (see the Healthymemory blog post titled, “The Ultimate Test”).

The authors of  “The Mind Club” also examine the other end of life.  That is, when does life begin.  This is a large religious issue that can impact people of different religious beliefs.  A symposium organized in 1968 by the Christian Medical Society affirmed that “the preservation of fetal life…may have to be abandoned to maintain full and secure family life, as well as in cases of rape, incest, fetal deformity, and threat to the mother’s well-being, whether physical or emotional.  However, evangelical opinion swung after church leaders such as the eminent Jerry Falwell reacted to the 1973 Roe v. Wade decision and advocate a “life at conception” interpretation of the Bible.   As the Catholic Church claims that life begins at conception certain Protestant sects did not want to appear remiss.

However, if memory serves healthy memory correctly, at one time there were arguments among Catholic philosophers as to when the soul entered the body.  Furthermore, healthy memory believes that there were different times depending upon whether a male of female was involved.  If any readers can help me out on this particular point, it would be much appreciated.

Nevertheless, it is healthymemory’s belief that the soul is the issue.  The soul is a religious entity and the argument should be argued in theological terms.  Biological terms are irrelevant.

© Douglas Griffith and healthymemory.wordpress.com, 2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

The Ultimate Test

April 7, 2016

The Ultimate Test is the sixth chapter of “Consciousness and the Brain:  Deciphering How the Brain Codes our Thoughts” is an outstanding book by the French neuroscientist Stanislas Dehaene who is the Chair of Experimental Psychology at the College of France.  This is the seventh consecutive post on this outstanding book. According to Dr. Dehaene the ultimate test of any theory of consciousness is the clinic.  Every year thousands of patients fall into a coma.  Unfortunately, many of these patients will remain permanently unresponsive in a dreaded condition called the “vegetative state.”  Worse yet, is that in Intensive Care Units (ICUs) over all the world, half of the deaths result from a clinical decision to remove life support.  How many of these decisions are wrongly made?

Coma is defined  clinically as a prolonged  loss of the capacity to be aroused.  However, coma patients are not brain-dead.  Brain death is a distinct state,characterized by a total absence of brain stem reflexes.  In brain-dead patients, positron emission tomography (PET) and other measures such as Doppler ultrasonography show that cortical metabolism and the perfusion of blood to the brain are annihilated.  Most countries, the Vatican included, identity brain death with death, period.

What is of primary interest is the “locked-in syndrome.”  This state typically results from a well-delimited lesion, usually on the protuberance of the brain stem.  Such a lesion disconnects the cortex the cortex from its output pathways  in the spinal cord.  If the cortex and the thalamus are spared, it often leaves consciousness intact.  As you can well imagine, this is a terrible state in which to find oneself.

The book “The Diving Bell and the Butterfly” (there is also an outstanding movie by the same name) was written by Jean-Dominique Baby, who was the editor of the French fashion magazine, “Elle.”  He wrote this book one character at a time by blinking his left eyelid while an assistant recited the letters of the alphabet.  He eloquently told his story with two hundred thousand blinks telling the story of a beautiful mind shattered by a cerebral stroke.  Fortunately he lived to se the book published, but, unfortunately, he died three days later.

Comparatively speaking, Jean-Domonique Baby was well-off. Many locked-in patients have no motor responses, no means of communicating with the world.  Fortunately fMRIs can identify these individuals, given enough time.  Unfortunately, fMRIs are extremely expensive and are beyond the budgets of too many medical facilities.  But, fortunately, Dr. Dehaene has developed an inexpensive test using EEG recordings using 256 electrodes.  Information exchanged over long cortical distances is an excellent index of consciousness in patients with brain lesions.  Computations are done for each pair of electrodes for a mathematical index of the amount of information shared by the underlying brain areas.  Vegetative-state patients showed a much smaller  amount of shared information than conscious patients and control patients.  This finding fits with  with a central tenet of global workspace theory, that information exchange is an essential function of consciousness.  A follow-up study showed that the few vegetative patients who showed high information sharing had a better chance of regaining consciousness within the next days or  months.

So technology and the global workspace theory provide good diagnostic techniques.  It is hoped that interventions will be developed in the future to unlock those in a locked-in state.  Dr. Dehaene has described some promising work being done in this area.

The Signatures of Conscious Thought

April 5, 2016

“The Signatures of Conscious Thought” is the fourth chapter of “Consciousness and the Brain:  Deciphering How the Brain Codes our Thoughts” is an outstanding book by the French neuroscientist Stanislas Dehaene who is the Chair of Experimental Psychology at the College of France.  This is the fifth consecutive post on this outstanding book.  In this chapter Dr. Dehaene discusses four reliable signatures of consciousness—physiological  markers that index whether the participant experienced a conscious percept.

The first signature is a sudden ignition of parietal and prefrontal circuits that is caused by a conscious stimulus (remember that the participant indicates whether the stimulus is conscious).

The second signature is found in the EEG in which conscious access is accompanied by a slow wave called the P3 wave, which emerges as late as one-third of a second after the stimulus.

The third signature is the result of conscious ignition that also triggers a late and sudden burst of high frequency oscillations.

The fourth signature  consists of many regions exchanging bidirectional messages over long distances in the cortes, which form a global brain web.

The conscious brain can perceive only a single chunk at a time.  Working memory rehearses these chunks to keep the active so they can be further processed.  The processing of a second chunk can be delayed if it occurs prior to the processing of the first chunk.  This is known as the psychological refractory period.

We can process a stimulus before we become consciously aware of the stimulus.  For example, if we place a hand on a hot stove, we’ll take it off the stove before we consciously perceive the pain caused by the hot stove.

Consciousness lives in  loops of reverberating neuronal activity, circulating in the web of our cortical connections, causing our conscious experience.

fMRI and scalp recording of brain potentials catch just a glimpse of the underlying brain activity.  Explorations of the third and fourth signatures require electrodes being placed directly inside the brain.  Such implantations of electrodes are indicated for certain epileptic patients, so science can capitalize on victims of this unfortunate malady.  I hope it provides some satisfaction to these patients that the data that is derived from these electrodes is greatly advancing science.

Subliminal stimuli can propagate  deeply into the cortex, but this brain activity is strongly amplified when the threshold for awareness is crossed, thus yielding reliable and valid signatures of consciousness.