The Phenomenal Power of the Mind

From Wikipedia, the free encyclopedia

The human brain is the most complex organ in the human body. It controls the central nervous system (CNS), by way of the cranial nerves and spinal cord, the peripheral nervous system (PNS) and regulates virtually all human activity.[1] Involuntary, or "lower," actions, such as heart rate, respiration, and digestion, are unconsciously governed by the brain,[1][2] specifically through the autonomic nervous system. Complex, or "higher," mental activity, such as thought, reason, and abstraction,[2] is consciously controlled.

The human brain is extremely complex. It contains some one hundred billion neurons,[1][2] which are capable of electrical and chemical communication with tens of thousands of other nerve cells.[1][2] Nerve cells in turn rely on some quadrillion (1015) synaptic connections for their communications.

Anatomically, the brain can be divided into three parts: the forebrain, midbrain, and hindbrain;[3] the forebrain includes the several lobes of the cerebral cortex that control higher functions, while the mid- and hindbrain are more involved with unconscious, autonomic functions. During encephalization, human brain mass increased beyond that of other species relative to body mass. This process was especially pronounced in the neocortex, a section of the brain involved with language and consciousness. The neocortex accounts for about 76% of the mass of the human brain;[4] with a neocortex much larger than other animals, humans enjoy unique mental capacities despite having a neuroarchitecture similar to that of more primitive species. Basic systems that alert humans to stimuli, sense events in the environment, and maintain homeostasis are similar to those of basic vertebrates. Human consciousness is founded upon the extended capacity of the modern neocortex, as well as the greatly developed structures of the brain stem.

The normal adult human brain typically weighs between 1 and 1.5 kg (3 lb) and has an average volume of 1.6 litres. The mature human brain consumes some 20-25% of the energy used by the body, while the developing brain of an infant consumes around 60%. Such heavy energy usage generates large quantities of heat, which must be continually removed to prevent brain damage. Both sexes have similar brain weight to body weight ratios,[5] though the differences in weight persist even when adjusted for relative body mass. Although no functional inference can be made from this statement, it does provide scientific proof that the weight for the brain of human males is larger and heavier than that of human females, usually by about 200 gramme (7 ounces). The human brain varies in many interesting ways between the sexes and may be an example of sexual dimorphism within the species (see also Sex and intelligence). It should also be noted that these differences in brain development and function may underlie the difference observed for weight and brain matter, and as such may not pertain directly to executive function since this faculty occurs by way of disparate neurophysiology for males and females.

The bulbous cerebral cortex is composed of convoluted grey matter internally supported by deep brain white matter. The two hemispheres of the brain are separated by a prominent central fissure and connect to each other at the corpus callosum. A well-developed cerebellum is found at the back of the brain. Brain stem structures are almost completely enveloped by the cerebellum and telencephalon, with the medulla oblongata projecting through the foramen magnum to merge with the spinal cord.

The blood supply to the brain involves the paired carotid arteries that enter the brain and communicate in the circle of Willis before branching out to their destinations. Further blood supply comes via the vertebral arteries. Blood drains from the brain through a network of sinuses that drain into the right and left internal jugular veins.

The brain is suspended in cerebrospinal fluid (CSF), which also fills spaces called ventricles inside it. The dense fluid protects the brain and spinal cord from shock; a brain that weighs 1,500 g in air weighs only 50 g when suspended in CSF (Livingston, 1965). Fluid movement within the brain is limited by the blood-brain barrier and the blood-cerebrospinal fluid barrier.

The brain is easily damaged by compression, so the fluid surrounding the central nervous system must be maintained at constant pressure. Humans are estimated to produce about 500 ml or more of cerebrospinal fluid each day, with only about 15 percent of the body's estimated 150 ml of CSF at any given time located in the ventricles of the brain. The remainder fills the subarachnoid space, which separates the soft tissues of the brain and spinal cord from the hard surrounding bones (skull and vertebrae). Elevated levels of CSF are associated with traumatic brain injury and hydrocephalus. Increased fluid pressure can result in permanent brain injury and death.

Anatomical restraints prevent the human brain from getting even bigger. At birth, an infant's skull is as large as it can be without imperiling the lives of mothers and infants during childbirth. The difficulty experienced by humans in giving birth is nearly unique in the animal kingdom, requiring the head of the emerging infant to be rotated as it passes through the birth canal. Female humans possess large pelvic openings to accommodate the birth of large-headed offspring, but at the cost of thinning of the pelvic bones. Bones too thin can no longer bear the mother's weight or the mechanical stresses of walking and running, and a compromised ability to flee dangers may prevent the female from coming of childbearing age.

At birth, the human skull is rather soft, and it deforms somewhat during its passage through the birth canal, then recovers its shape. This allows it to expand to make room for the brain, which continues to grow, at the same rate as that of an unborn fetus, for an additional year. In all other animals the growth rate of the brain slows significantly at birth.

Function

A sketch of the human brain by artist Priyan Weerappuli, imposed upon the profile of Michelangelo's David.

The human brain is the source of the conscious, cognitive mind. The mind is the set of cognitive processes related to perception, interpretation, imagination, memories, and crucially language (cf. Broca's area) of which a person may or may not be aware. Beyond cognitive functions, the brain regulates autonomic processes related to essential body functions such as respiration and heartbeat.

Extended neocortical capacity allows humans some control over emotional behavior, but neural pathways between emotive centers of the brain stem and cerebral motor control areas are shorter than those connecting complex cognitive areas in the neocortex with incoming sensory information from the brain stem. Powerful emotional pathways can modulate spontaneous emotive expression regardless of attempts at cerebral self-control. Emotive stability in humans is associated with planning, experience, and an environment that is both stable and stimulating.

The 19th century discovery of the primary motor cortex mapped to correspond with regions of the body led to popular belief that the brain was organized around a homunculus. A distorted figure drawn to represent the body's motor map in the prefrontal cortex was popularly recognized as the brain's homunculus, but function of the human brain is far more complex than this simple figure suggests. A similar, "sensory homunculus" can be drawn in the parietal lobe that parallels that in the frontal lobe.

The human brain appears to have no localized center of conscious control. The brain seems to derive consciousness from interaction among numerous systems within the brain. Executive functions rely on cerebral activities, especially those of the frontal lobes, but redundant and complementary processes within the brain result in a diffuse assignment of executive control that can be difficult to attribute to any single locale.

Midbrain functions include routing, selecting, mapping, and cataloging information, including information perceived from the environment and information that is remembered and processed throughout the cerebral cortex. Endocrine functions housed in the midbrain play a leading role in modulating arousal of the cortex and of autonomic systems.

Nerves from the brain stem complex where autonomic functions are modulated join nerves routing messages to and from the cerebrum in a bundle that passes through the spinal column to related parts of a body. Twelve pairs of cranial nerves, including some that innervate parts of the head, follow pathways from the medulla oblongata outside the spinal cord.

A definite description of the biological basis for consciousness so far eludes the best efforts of the current generation of researchers. But reasonable assumptions based on observable behaviors and on related internal responses have provided the basis for general classification of elements of consciousness and of likely neural regions associated with those elements. Researchers know people lose consciousness and regain it, they have identified partial losses of consciousness associated with particular neuropathologies and they know that certain conscious activities are impossible without particular neural structures.

More than likely you said, "A bird in the bush,"! and. .......if this IS what YOU said, then you failed to see that the word THE is repeated twice!

Sorry, look again. Next, let's play with some words.

What do you see?

Stretch your brain This is not a test - just a phenomenon. All readings are explained. Read out loud the text inside the triangle ABOVE.

In black you can read the word GOOD, in white the word EVIL (inside each black letter is a white letter). It's all very physiological too, beca use it visualize the concept that good can't exist without evil (or the absence of good is evil). Now, what do you see?

You may not see it at first, but the white spaces read the word optical, the blue landscape reads the word illusion. Look again! Can you see why this painting is called an optical illusion?

What do you see here?

This one is quite tricky!

The word TEACH reflects as LEARN.

Last one.

What do you see?

You probably read the word ME in brown, but.......

when you look through ME you will see YOU!

Do you need to look again?

Count every " F " in the following text:

FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS... (SEE BELOW)

HOW MANY ? WRONG, THERE ARE 6 -- no joke. READ IT AGAIN !

Really, go Back and Try to find the 6 F's before you scroll down.

The reasoning behind is further down.

The brain cannot process "OF". & nbsp;

Incredible or what? Go back and look again!!

Anyone who counts all 6 "F's" on the first go is a genius.

Three is normal, four is quite rare. Let your friend read this and test. It will drive them crazy.! And keep them occupied for several minutes..!

O lny srmat poelpe can raed tihs.

I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rgh it pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt! if you can raed tihs psas it on !!

Psas Ti ON !