Biology - Brain

Brain Waves

When you drop a small stone in water, you see waves. Similarly our heart and our brain have wave patterns. The wave pattern of the heart is measured by ECG (electro cardiograph). The brain waves are measured by EEG (electro encephalograph).

Using the brain wave studies, scientists have discovered that our brain waves are of four types.

The brain waves also have peaks that are similar to the peaks we see in water waves. The number of times the peak appears in one second is called "cycles per second". For example, the electricity in India is of 50 cycles per second.

Beta (13 to 25 cycles per second)

This brain wave indicates that your conscious mind is in control. It indicates a mental state of logical thought, analysis, and action. You are alert and awake talking, speaking, doing, solving problems, etc.

Alpha (8 to 12 cycles per second)

This brain wave indicates relaxation and meditation. It is a state of relaxed alertness good for inspiration, learning facts fast.

Theta (4 to 8 cycles per second)

Deep meditation. This is associated with life-like imagination. This is best for suggestibility and inspiration. This brain wave is dominant in children of age 2 to 5.

Delta (0.5 to 4 cycles per second)

Deep dreamless sleep. Deep relaxation.

Left brain and right brain working together

Usually the left brain and the right brain waves are independent. They reach peaks independent of each other. During meditation and deep relaxation, the left brain waves and the right brain waves happen together. For both, the peaks are reached together. This is called synchronization. Scientists now believe that synchronization makes much greater mind power available. This is associated with learning large amounts of information very quickly as well as with creativity. Brain self-control

Scientists had long believed that brain activity such as brain waves and secretion of brain chemicals were beyond conscious control. But, experiments on Swami Rama of the Himalayas and on biofeedback have now changed that belief. Now it is proven that some people can control their brain waves, etc.

Brain parses 'movies of our lives' into small meaningful chunks

June 27, 2001 - Reuters

With so much of our modern lives dominated by movies and television, it's easy to think of perception as a continuous, unedited, uncut version of the world around us. But new research from Washington University in St. Louis suggests that while we are watching the "movies" of our daily lives, the brain is automatically dividing them into smaller, meaningful units.

Jeffrey M. Zacks, Ph.D., assistant professor of psychology in Arts and Sciences, and colleagues, identified a network of brain areas that is activated during the perception of boundaries between events.

"We found regions of activity in the brain that track the process of identifying parts of continuous events, whether or not people are aware of those parts or even know anything about them," said Zacks. The study is published in the June 2001 issue of Nature Neuroscience.

The researchers observed local brain activity using functional magnetic resonance imaging (fMRI) while participants watched movies of common, everyday goal directed activities, such as making the bed, doing the dishes, or ironing a shirt. In the first scan, participants were instructed to passively watch the movies. These scans revealed that the brain automatically parses continuous events into smaller segments even in the absence of explicit instructions to do so.

"To answer the question about whether event segmentation is an ongoing process, we needed data from when people were not performing any task. So we had them just sit and watch the movies," Zacks said. "The fact that changes in brain activity occurred during the passive viewing of movies indicates that this is how we normally perceive continuous events, as a series of segments rather than a dynamic flow of action."

In two later scans, the same movies were shown again, but participants were instructed to press a hand-held button every time they identified a specific small task -- rinsing, washing, drying, for instance -- that was a necessary component of the larger activity. In one of the later scans, participants were asked to divide the movie into the largest units that were natural and meaningful to them; in the other scan, the smallest units.

These later scans allowed the researchers to look at brain activity during the perception of boundaries between large and small events. "We found local changes in brain activity occurring at the same time people were identifying event boundaries, and throughout this network, changes were larger for large boundaries and smaller for small ones," Zacks said.

Similar changes were observed when participants were passively viewing movies, although to a lesser degree. These findings also confirm previous behavioral work on the hierarchical structure of event segmentation, whereby large meaningful segments correspond to groups of smaller meaningful segments.

The activated parts of the brain include a large bilateral region of the posterior cortex, and a smaller region in the right frontal cortex. The peak of activity in the posterior cortex is in the human MT (or V5) complex, an area responsible for understanding motion and human action.

Activity in the frontal cortex was localized to a part of the frontal eye field (FEF) that is associated with shifting attention. How we form our perceptions has long been a basic question in cognitive science. While much previous research has yielded interesting clues about how we form perceptions in space, much less is known about how we form perceptions across time.

These findings have important practical implications because insights into how the brain processes and perceives individual tasks and activities could be harnessed to suggest more direct and effective approaches to everything from elementary curricula to on-the-job training.

Scientist Says Mind Continues After Brain Dies

June 27, 2001 - Reuters

A British scientist studying heart attack patients says he is finding evidence that suggests that consciousness may continue after the brain has stopped functioning and a patient is clinically dead.

The research, presented to scientists last week at the California Institute of Technology (Caltech), resurrects the debate over whether there is life after death and whether there is such a thing as the human soul.

``The studies are very significant in that we have a group of people with no brain function ... who have well-structured, lucid thought processes with reasoning and memory formation at a time when their brains are shown not to function,'' Sam Parnia, one of two doctors from Southampton General Hospital in England who have been studying so-called near-death experiences (NDEs), told Reuters in an interview.

``We need to do much larger-scale studies, but the possibility is certainly there'' to suggest that consciousness, or the soul, keeps thinking and reasoning even if a person's heart has stopped, he is not breathing and his brain activity is nil, Parnia said.

He said he and colleagues conducted an initial yearlong study, the results of which appeared in the February issue of the journal Resuscitation. The study was so promising the doctors formed a foundation to fund further research and continue collecting data.

During the initial study, Parnia said, 63 heart attack patients who were deemed clinically dead but were later revived were interviewed within a week of their experiences.

Of those, 56 said they had no recollection of the time they were unconscious and seven reported having memories. Of those, four were labeled NDEs in that they reported lucid memories of thinking, reasoning, moving about and communicating with others after doctors determined their brains were not functioning.


Among other things, the patients reported remembering feelings of peace, joy and harmony. For some, time sped up, senses heightened and they lost awareness of their bodies.

The patients also reported seeing a bright light, entering another realm and communicating with dead relatives. One, who called himself a lapsed Catholic and Pagan, reported a close encounter with a mystical being.

Near-death experiences have been reported for centuries but in Parnia's study none of the patients were found to have received low oxygen levels, which some skeptics believe may contribute to the phenomenon.

When the brain is deprived of oxygen people become totally confused, thrash around and usually have no memories at all, Parnia said. ``Here you have a severe insult to the brain but perfect memory.''

Skeptics have also suggested that patients' memories occurred in the moments they were leaving or returning to consciousness. But Parnia said when a brain is traumatized by a seizure or car wreck a patient generally does not remember moments just before or after losing consciousness.

Rather, there is usually a memory lapse of hours or days. ''Talk to them. They'll tell you something like: 'I just remember seeing the car and the next thing I knew I was in the hospital,''' he said.

``With cardiac arrest, the insult to the brain is so severe it stops the brain completely. Therefore, I would expect profound memory loss before and after the incident,'' he added.

Since the initial experiment, Parnia and his colleagues have found more than 3,500 people with lucid memories that apparently occurred at times they were thought to be clinically dead. Many of the patients, he said, were reluctant to share their experiences fearing they would be thought crazy.


One patient was 2-1/2 years old when he had a seizure and his heart stopped. His parents contacted Parnia after the boy ''drew a picture of himself as if out of his body looking down at himself. It was drawn like there was a balloon stuck to him. When they asked what the balloon was he said, 'When you die you see a bright light and you are connected to a cord.' He wasn't even 3 when had the experience,'' Parnia said.

``What his parents noticed was that after he had been discharged from hospital, six months after the incident, he kept drawing the same scene.''

The brain function these patients were found to have while unconscious is commonly believed to be incapable of sustaining lucid thought processes or allowing lasting memories to form, Parnia said -- pointing to the fact that nobody fully grasps how the brain generates thoughts.

The brain itself is made up of cells, like all the body's organs, and is not really capable of producing the subjective phenomenon of thought that people have, he said.

He speculated that human consciousness may work independently of the brain, using the gray matter as a mechanism to manifest the thoughts, just as a television set translates waves in the air into picture and sound.

``When you damage the brain or lose some of the aspects of mind or personality, that doesn't necessarily mean the mind is being produced by the brain. All it shows is that the apparatus is damaged,'' Parnia said, adding that further research might reveal the existence of a soul.

``When these people are having experiences they say, 'I had this intense pain in my chest and suddenly I was drifting in the corner of my room and I was so happy, so comfortable. I looked down and realized I was seeing my body and doctors all around me trying to save me and I didn't want to go back.

``The point is they are describing seeing this thing in the room, which is their body. Nobody ever says, 'I had this pain and the next thing I knew my soul left me.'''

Key to Recognizing Self Linked to Right Side of Brain

January 18, 2001 - Reuters - London

If the face in the photo isn't familiar and it's your own, chances are there could be a problem in the right side of the brain.

In research published in the science journal Nature on Wednesday, scientists at Beth Israel Deaconess Medical Center in Boston have shown that the ability to recognize who we are is linked to brain activity in one side of the brain.

"It's not an all or nothing phenomenon, but recognizing one's own face appears to be a preferential ability of the right hemisphere,'' said Julian Keenan, a cognitive psychologist at the Massachusetts hospital.

He and his colleagues tested the ability of five epilepsy patients being tested for brain surgery to recognize themselves in an image morphed with an image of a famous person. In the pre-operative tests each side of the brain was anesthetized.

Each female patient was morphed with image of Marilyn Monroe or Princess Diana, while the men assumed the likeness of Bill Clinton or Albert Einstein.

Afterwards all of the patients remembered their own image when the morphed image was shown while the left side of the brain was anesthetized, but four recognized the famous person when the right side was numbed.

In another experiment the scientists monitored the brain activity of 10 healthy hospital employees while they looked at a morphed image of themselves and a famous person and another image of a morphed colleague.

The researchers noticed more brain activity on the right side of the brain when the staff members looked at their own morphed image.

``One of the astonishing findings in psychology is that humans and apes are the only species that recognize their own faces in mirrors,'' Keenan said in a statement.

``It has been thought that this ability is a hallmark of consciousness. To know that our own face is ours inevitably requires a knowledge of the self. Without self-knowledge, it would be seemingly impossible to recognize who we are,'' he added.

Researchers Identify Brain's Moral Center

May 5, 2000 - Reuters - San Diego

The brain's moral center--the bit that sorts "right'' from "wrong'' has been identified on brain scans, researchers reported here at the American Academy of Neurology's 52nd annual meeting.

Drs. Ricardo de Oliveira-Souza and Jorge Moll of the Neurology and Neuroimaging Group, LABS and Hospitais D'or, Rio de Janeiro, Brazil, used magnetic resonance imaging (MRI) to find out which parts of the brain were working when people were asked to make moral judgments.

Ten subjects (six men and four women), aged 24 to 43 years, were asked to make a series of moral judgments while lying inside an MRI scanner.

On headphones, the study participants listened to a series of statements, such as ``we break the law if necessary,'' ''everyone has the right to live,'' and ``let's fight for peace.'' In each case, the subjects were asked to silently judge if each sentence was "right'' or ``wrong.''

The participants also listened to sentences with no moral content, such as ``stones are made of water'' or ``walking is good for health,'' and judged these in a similar fashion.

Results from brain scans taken as these judgments were being considered showed that making moral choices was associated with activation of the brain's frontal poles - an area known as Brodmann area 10.

According to the research team, their findings tie in with previous observations that people who injure this area of the brain may exhibit severe antisocial activity.

Researchers identify molecule crucial to adjusting body's internal clock

December 1, 1999 - AP - Champaign, Ill.

Is your biological clock out of kilter? Researchers say they have identified an important molecule in the retina-brain pathway that is crucial to adjusting the clock.

In the Nov. 9 issue of the Proceedings of the National Academy of Sciences, the scientists point a finger at pituitary adenylyl cyclase-activating peptide (PACAP), whose function had been a mystery. In both animal and cellular studies, they found that PACAP works in concert with glutamate, another molecule in the nerve fibers between the retina and hypothalamus, home of the circadian clock.

"This study provides insight as to how the complex external signals that we encounter daily, such as the range of light intensities, are encoded and communicated to the brain," said Martha Gillette, the head of the department of cell and structural biology at the University of Illinois. "Light that you experience at night triggers the release of both glutamate and PACAP. The ratio probably depends on the intensity of the light stimulus."

Gillette's lab in 1994 reported that glutamate adjusts the clock in the presence of light at night. "PACAP fine tunes the glutamate signal," she said. "Together they convey more than just light is present. They encode information about light properties that is taken back to the clock, allowing it to adjust forward or backward appropriately."

The study - funded by the National Institute of Neurological Disorders and Stroke and the Danish Medical Research Council - focused on PACAP after a Danish group discovered that the molecule was localizing in the neural pathway. The question became what was PACAP doing?

"Adding exogenous PACAP together with glutamate had a negative effect on the amplitude of the clock-resetting effect of glutamate, which itself has the same effect on clock-resetting as light under laboratory conditions," Gillette said. "The surprise was that when we used fragments of the PACAP peptide as a control, the result was not that of glutamate alone. Rather, the effect was shifted in the opposite direction to increasing PACAP."

Applying antibodies to block the effect of PACAP that might be released from the optic nerve fibers in brain-slice preparations had the same effect. "This meant that PACAP was indeed released from the optic nerve when the glutamate was. It is a normal, silent component of the signal," she said.

This is likely the basis for why bright light at night keeps a person awake more effectively than dim light, Gillette said. Bright light delays clock time more and, thereby, makes it harder to awaken early the next morning. More PACAP in the light signal means a greater delay, she added.

Eventually, Gillette said, it may be possible to create drugs to selectively reset a person's sleep cycle, which would be welcome news for night-shift workers and for some people with sleep disorders.

The co-authors of the paper were Gillette, Dong Chen, Gordon F. Buchanan and Jian M. Ding, all of the U. of I., and Jens Hannibal, a professor of clinical biochemistry at the University of Copenhagen.