Brain Facts:
Anatomy of the Brain

Amygdala

The amygdala automatically and compulsively scans everyone we encounter for whether they are to be trusted…Neurological patients who have extensive amygdala damage are unable to make judgment of how trustworthy someone might be.

Amygdala

The amygdala, in the midbrain below the cortex, handles automatic emotional processes; the prefrontal cortex, in its executive function, draws inputs from many other neural regions, integrates them, and makes plans accordingly.

Amygdala

Emotions, especially fear and anxiety, are the responsibility of the amygdala. This almond-shaped brain area, located above each ear, triggers the fight-or-flight response that arouses animals to run away from danger or attack its source.

Amygdala
—Damage

Amygdala damage makes people behave more like theoretical machines. “Strangely enough, people with damage to the emotional system are, paradoxically, more rational in making certain types of decisions. Their decisions don’t take into account any emotional processing.

Amygdala
—Fear

The amygdala spots signs of fear in someone’s face with remarkable speed, picking it up in a glimpse as quick as 33 milliseconds, and in some people even in a mere 17 millisecond (less than two hundredths of a second).

Amygdala
—Fear

The cells in the amygdala where sensory information registers, and the adjacent areas that acquire fear, actually fire new patterns at the moment a fear has been learned.

Amygdala
—Gambling

We think this shows that the amygdala is critical for triggering a sense of caution toward making gambles in which you might lose," explains Camerer. This function of the amygdala, he says, may be similar to its role in fear and anxiety.
"Loss aversion has been observed in many economic studies, from monkeys trading tokens for food to people on high-stakes game shows," he adds, "but this is the first clear evidence of a special brain structure that is responsible for fear of such losses."

Amygdala
—OFC

The OFC exerts a “top-down” modulation of the amygdala, the source of unruly emotional surges and impulses. Like small children, patients who have lesions in these inhibitory circuits typically lose the ability to suppress emotional impulses, unable for example to keep themselves from mimicking someone’s scowling face. Lacking this emotional safety device, their rambunctious amygdala has free rein.

Amygdala
—Smells

The amygdala supervises not only the formation of emotional experiences but also the memory of emotional experiences. Because smell directly stimulates the amygdala, smell directly stimulates emotions. Smell signals also head through the piriform cortex to the orbitofrontal cortex, a part of your brain just above and behind your eyes and the deeply involved in decision making. So smell plays a role in decision making.

Attention Deficit Disorder

Brain images show that the brains of adult and children with attention deficit disorder have abnormalities in the way they burn glucose. Similarly, images show that schizophrenic brains are different from normal brains.

Basal Ganglia

Below the cerebral hemispheres lies a group of nuclei (collections of nerve cells) that organize movement. These nuclei, called the basal ganglia, enable you to do such things as skillfully maneuver your way through heavy traffic while simultaneously rehearsing what you’re going to say at the business meeting later in the morning. In computer terms, the cerebral cortex writes the software programs for actions and, after some practice on your part, the basal ganglia take over to run the programs that enable you to carry out the actions.

Blood flow to organs fluctuates greatly according to their needs and general body activity: when we are resting, they require less blood; during physical activity, they need more. But the brain’s need for blood is different. It remains almost constant, flowing through at 1 ½ pints per minute no matter what the brain or body is doing – from resting to intense thought, such as reading a book, or hard physical exercise.

The brain needs this constant supply because it cannot store its fuel. And just 5 to 10 seconds without oxygen flowing to the brain causes a person to lose consciousness. After four minutes, serious damage begins in the neurons and other brain cells. Just 10 minutes after the initial loss of supply, this damage is usually irreversible—and fatal.

Brain Cells
—Connections

According to the scientific evidence, whenever we push ourselves to solve problems in a new way, we may be strengthening the connections between our brain cells. Each brain cell has dendrites. These minute extensions—similar to branches of a tree—pass information along from brain cell to brain cell. Without use, our dendrites can atrophy or shrink; but when we exercise them in new and creative ways, their connections remain active, passing new information along. Basically, any conscious effort to exercise your brain can potentially create new brain cell connections. And, remarkably, new dendrites can still be created even if old ones have already died.

Brain
—Energy

The brain’s appetite for energy is enormous. The brain represents only about 2 percent of the body’s total energy usage—about 10 times more than would be expected. When the brain is fully working, it uses more energy per unit of tissue weight than a fully exercising quadriceps. In fact, the human brain cannot simultaneously activate more than 2 percent of it neurons at any one time. More than this and the glucose supply becomes so quickly exhausted that you will faint.

Three layers of the brain are known for distinct functions (though all functioning areas constantly interact).

Brain stem (fight or flight, instinct)

Limbic system (emotion is processed)

Brain
—Parts

Brain
—Growth

Two pivotal notions about the nature of the brain have been nullified. One is that the brain ceases to grow and change after childhood. The second is that the brain steadily loses brain cells after age twenty or so and consequently relentlessly declines in mental capacity.

Brain
—Quality

The amount of brain mass is not a true test of a brain’s quality. Scientist used to think so, but now they believe how elaborate the neuronal networks are and the strength of their connections and circuitry really count more than the brute number of brain cells.

Brain
—Receiving Information

Your brain takes in formation from the world thought the senses. Even if you are sitting quietly in a room, you brain receives far more information that it can hold on to, or than you need to decide how to act.

Brain Stem

Located at the very bottom of the brain, where it is attached to the spinal cord. This region controls basic functions that are critical for life, like reflexive movements of the head and eyes, breathing, heart rate, sleep arousal, and digestion. This stuff is really important, but you don’t usually notice it happening.

Audible speech in Broca’s Area, versus Wernicke’s area.

Broca’s Area

Broca’s area activated during audible speech or reading aloud, located toward the center of the frontal lobe in the left hemisphere. First however, the brain must assemble appropriate words in Wernicke’s area and then relay them to Broca’s area for transshipment to the motor cortex that controls speech production.

Paul Broca, a young surgeon, eventually pinpointed the area of the brain involved in instances of conscious speech loss (circa 1864). It has since come to be known as Broca’s area.

Broca’s Rule

Broca considered the relationship between handedness and speech. He suggests that both speech and manual dexterity are attributable to the inborn superiority of the left hemisphere in right-handers. “One can conceive that there may be a certain number of individuals in whom the natural pre-eminence of the convolutions of the right hemisphere reverses the order of the phenomenon which I have described.” These individuals, of course, are left-handers.
Broca’s rule that the hemisphere controlling speech is on the side opposite the preferred hand was influential well into the twentieth century. The rule accounted nicely for the relationship between damage to the left hemisphere and aphasia in right-handers.

Cells

Your brain is made of cells. Brain cells come in two types: neurons, which talk to one another and to the rest of the body, and glial cells, which provide essential support to keep the whole show going. Your brain is made up of one hundred billion neurons—which have a long skinny, complicated shape—and many more glial cells.

Cerebral Cortex

Cerebral Cortex

The cerebral cortex consists of the outer gray matter of the cerebral hemispheres and the cerebellum, the two structures that contain most of the neurons of the brain. Less than a quarter inch in thickness, this thin rink includes some 85 percent of all train tissue.

Richard Restak
Mozart’s Brain and the Fighter Pilot
p. 20

This is where thinking occurs, consciously. The pre-frontal cortex handles most of our decision making. Different sensory stimulants are also processed.

Central Pattern Generator

Your ability to generate rhythms simultaneously shows that your brain can generate multiple patterns at once, often independently. Walking involves a tightly coordinated set of events in which your left leg is instructed to rise, move forward, and then lower as your body simultaneously moves forward. Your right leg follows close behind. The sequence of events has to happen smoothly and in order. These commands are generated mainly by a network of neurons in you spinal cord, all working together as what’s called a central pattern generator—central because commands originate here and go to the muscles.

Cerebellum

The cerebellum, a large region at the back of the brain, integrates sensory information to help guide movement.

Cortex

The cortex is connected to the body by more primitive “sub-cortical” structures that regulate basic life-support systems, the activity of hormones, and primal emotions. The subcortical structures connect the neocortex to the brain stem, which in turn connects the brain to the spinal cord, and the biological process of the body.. So the cerebral cortex is also an important center of sensory and motor control. It is where mind and body come together and create our self-image and our view of the world.

Cortex

The cortex is the largest part of the human brain, making up a little over three-fourths of its weight, and it’s shaped like a large crumpled-up comforter that wraps the top and sides of the brain.

Cortex
Frontal Lobe

Part of the cortex, the frontal lobe generates movement commands, contains the area that produces speech, and is responsible for selecting appropriate behavior depending on your goals and environments.

Cortex Occipital Lobe

Part of the cortex, the occipital lobe is located in the back of your brain and is responsible for visual perceptions.

Cortex Parietal Lobe

Part of the cortex, the parietal lobe, on the top and sides, receives information from the skin senses. It also puts together information from all the senses and figures out where to direct your attention.

Cortex Temporal Lobe

Part of the cortex, the temporal lobe, just above your ears, is involved in hearing and contains the area that understands speech. It also interacts closely with the amygdala and hippocampus and is important to learning, memory, and emotional response.

Gray Matter

'Grid cells' that act like a spatial map in the brain have been identified for the first time in humans, according to new research by UCL scientists which may help to explain how we create

The study is by a team from the UCL Institute of Cognitive Neuroscience and was funded by the Medical Research Council and the European Union. Published in Nature, it uses brain imaging and virtual reality techniques to try to identify grid cells in the human brain. These specialised neurons are thought to be involved in spatial memory and have previously been identified in rodent brains, but evidence of them in humans has not been documented until now.

Grid cells represent where an animal is located within its environment, which the researchers liken to having a satnav in the brain. They fire in patterns that show up as geometrically regular, triangular grids when plotted on a map of a navigated surface. They were discovered by a Norwegian lab in 2005 whose research suggested that rats create virtual grids to help them orient themselves in their surroundings, and remember new locations in unfamiliar territory.

Study co-author Dr Caswell Barry said: "It is as if grid cells provide a cognitive map of space. In fact, these cells are very much like the longitude and latitude lines we're all familiar with on normal maps, but instead of using square grid lines it seems the brain uses triangles.
Lead author Dr Christian Doeller added: "Although we can't see the grid cells directly in the brain scanner, we can pick up the regular six-fold symmetry that is a signature of this type of firing pattern. Interestingly, the study participants with the clearest signs of grid cells were those who performed best in the virtual reality spatial memory task, suggesting that the grid cells help us to remember the locations of objects."

Professor Neil Burgess, who leads the team, commented: "The parts of the brain which show signs of grid cells -- the hippocampal formation and associated brain areas -- are already known to help us navigate our environment and are also critical for autobiographical memory. This means that grid cells may help us to find our way to the right memory as well as finding our way through our environment. These brain areas are also amongst the first to be affected by Alzheimer's disease which may explain why getting lost is one of the most common early symptoms of this disease."

Hippocampus

According to recent research, brain cells continue to multiply in the hippocampus, an important center for learning and memory. In addition, the brain is not a static structure, but exhibits a remarkable plasticity over time according to the richness of a person’s experience.

Hippocampus

The Hippocampus stores facts and place information and is necessary for long-term memory.

History
—Wilder Penfield

In the early 1930’s, Wilder Penfield and his associates at the Montreal Neurological Institute pioneered the use of surgery, removing the area of the brain where the abnormal activity begins as a treatment for epilepsy in patients who did not respond well to drug therapy…Preliminary work in the early 1900’s had shown that because the brain itself does not contain pain receptors, it is possible for a patient to remain fully conscious while a neurosurgeon removes a flap of skull under local anesthesia and applies small electrical currently directly to different regions of the brain surface.

Human Life
—Three requirements

The three requirements for human life are food, drink, and fresh air. You can live for 30 days or so without food, and you can go for a week or so without drinking water. Your brain, however, is so active that it cannot go without oxygen for more than 5 minutes without risking serious and permanent damage. Toxic electrons over-accumulate because the blood can’t deliver enough oxygen sponges.

Hypothalamus

Controls basic function processes that are important to life, but it gets the fun jobs. Its responsibilities include the release of stress and sex hormones and the regulation of sexual behaviors, hunger, thirst, body temperature, and daily sleep cycles.

Scientists at Albert Einstein College of Medicine of Yeshiva University have found that a "longevity gene" helps to slow age-related decline in brain function in older adults. Drugs that mimic the gene's effect are now under development, the researchers note, and could help protect against Alzheimer's disease.

The paper describing the Einstein study is published in the January 13 edition of the Journal of the American Medical Association.
"Most work on the genetics of Alzheimer's disease has focused on factors that increase the danger," said Richard B. Lipton, M.D., the Lotti and Bernard Benson Faculty Scholar in Alzheimer's Disease and professor and vice chair in the Saul R. Korey Department of Neurology at Einstein and senior author of the paper. As an example, he cites APOE ε4, a gene variant involved in cholesterol metabolism that is known to increase the risk of Alzheimer's among those who carry it.
"We reversed this approach," says Dr. Lipton, "and instead focused on a genetic factor that protects against age-related illnesses, including both memory decline and Alzheimer's disease."

In a 2003 study, Dr. Lipton and his colleagues identified the cholesteryl ester transfer protein (CETP) gene variant as a "longevity gene" in a population of Ashkenazi Jews. The favorable CETP gene variant increases blood levels of high-density lipoprotein (HDL) -- the so-called good cholesterol -- and also results in larger-than-average HDL and low-density lipoprotein (LDL) particles.

The researchers of the current study hypothesized that the CETP longevity gene might also be associated with less cognitive decline as people grow older. To find out, they examined data from 523 participants from the Einstein Aging Study, an ongoing federally funded project that has followed a racially and ethnically diverse population of elderly Bronx residents for 25 years.

At the beginning of the study, the 523 participants -- all of them 70 or over -- were cognitively healthy, and their blood samples were analyzed to determine which CETP gene variant they carried. They were then followed for an average of four years and tested annually to assess their rates of cognitive decline, the incidence of Alzheimer's disease and other changes.

"We found that people with two copies of the longevity variant of CETP had slower memory decline and a lower risk for developing dementia and Alzheimer's disease," says Amy E. Sanders, M.D., assistant professor in the Saul R. Korey Department of Neurology at Einstein and lead author of the paper. "More specifically, those participants who carried two copies of the favorable CETP variant had a 70 percent reduction in their risk for developing Alzheimer's disease compared with participants who carried no copies of this gene variant."

The favorable gene variant alters CETP so that the protein functions less well than usual. Dr. Lipton notes that drugs are now being developed that duplicate this effect on the CETP protein. "These agents should be tested for their ability to promote successful aging and prevent Alzheimer's disease," he recommends.
The research was funded by the National Institute on Aging, one of the 27 institutes and centers of the National Institutes of Health.

Modification

Think of the brain as a work in progress that continues from birth until the day you die. At every moment, you activities and thoughts are modifying you brain. That modification can lead to enhanced brain performance and capabilities. This hold true no matter what you age or how late in life you begin.

Paul MacLean

It was NIMH Researcher Paul Mac Lean who popularized the concept of the limbic system as the seat of the emotions. The limbic system was one constituent of his triune brain theory, which held that there are three layers to the human brain, representing different stages of humanity’s evolution—the brain stem (hindbrain), or reptilian brain, which is responsible for breathing, excretion, blood flow, body temperature, and the automatic functions; the limbic system, which encircles the top of the brainstem and is the seat of the emotions; and the cerebral cortex, in the forebrain, which is the seat of reason.

Prefrontal Lobes

It’s the prefrontal lobes that engineer premotor programs. After formulating the programs, the prefrontal lobes dispatch their orders to the motor cortex and the cerebellum, which together carry out the desired actions.

Prefrontal Lobes

The prefrontal lobes are principally responsible for four control functions.
Sequencing. We are capable of handling sequential information, maintaining it accurately and in proper sequence, and, finally, reorganizing it for later processing. After you’ve read a book, you may want to later summarize it for a friend. This will require sequencing.
Drive. To remain alert and aware of events and people around us required the ability to pay attention and stay focused. While people vary in their capacity to do this, children and adults with attention deficit disorder (ADD) have the greatest difficulty. Their problem, according to recent research, stems from malfunctions in the frontal lobes.
Executive Control. This is what really separates us from all other high primates. We can anticipate the potential consequences of our actions. We can monitor the responses we’re eliciting from other people. And we can simultaneously manage several different processes at once.
Future Memory. Future memory refers to your ability to look forward to future goals and keep them in mind in the present so that current inconveniences don’t sidetrack you. People with frontal lobe disorders experience great difficulty imagining themselves in any situation other than where they are now.

Prefrontal and Frontal Lobes

Our frontal and prefrontal lobes are responsible for our ability to project ourselves into the future. The prefrontal lobes come up with the intention and the frontal lobes, via their motor connections, carry it out.

Premotor Programming

Premotor programming also underlies all of the advice you’ve ever heard about the power of positive thinking. We eventually become the products of the images we entertain about ourselves.

Synapse

At the synapse, communication changes from an electrical impulse to a chemical one. Neurotransmitters (chemical messengers) are released from the messenger cell and diffuse across the synapse to lock onto a specialized receptor.

Thalamus

Sensory information entering the body through the eyes, ears, and skin travel in the forms of spikes to the thalamus, in the center of the brain, which filters the information and passes it along, as more spikes to the cortex.

Vision
—Cone Cells

Three different types of so-called cone cells in the retina detect red, green, or blue colors in bright light; these neurons send increasingly strong signals as the intensity of the light that they detect becomes stronger. Other colors are formed by different levels of activity in combination of these three cell types. A fourth cell type, call a rod, detects light intensity in dim light but does  not contribute to color vision, which is why you can’t see colors as well when the lighting is romantic.

Visual
—Pictorial Superiority Effect

The more visual the input becomes, the more likely it is to be recognized—and recalled. The phenomenon is so pervasive, it has been given its own name: the pictorial superiority effect, or PSE.

Text and oral presentations are not just less efficient than pictures for retaining certain types of information; they are way less efficient. If information is presented orally, people remember about 10 percent, tested 72 hours after exposure. That figure goes up to 65 percent if you add pictures.

Visual
—Experience

We actually experience our visual environment as a fully analyzed opinion about what the brain thinks is out there.

Visual
—Resources

The brain has to devote to vision a lot of thinking resources. It takes up about half of everything you do.