Related topics: brain cells
Human brain
hideThe human brain is the center of the human nervous system and is a highly complex organ. Enclosed in the cranium, it has the same general structure as the brains of other mammals, but is over three times as large as the brain of a mammal with an equivalent body size. Most of the expansion comes from the cerebral cortex, a convoluted layer of neural tissue that covers the surface of the forebrain. Especially expanded are the frontal lobes, which are involved in executive functions such as self-control, planning, reasoning, and abstract thought. The portion of the brain devoted to vision is also greatly enlarged in humans.
Brain evolution, from the earliest shrewlike mammals through primates to hominids, is marked by a steady increase in encephalization, or the ratio of brain to body size. The human brain has been estimated to contain 50–100 billion (1011) neurons[citation needed], of which about 10 billion (1010) are cortical pyramidal cells.[citation needed] These cells pass signals to each other via approximately 100 trillion (1014)[citation needed] synaptic connections.
In spite of the fact that it is protected by the thick bones of the skull, suspended in cerebrospinal fluid, and isolated from the bloodstream by the blood-brain barrier, the delicate nature of the human brain makes it susceptible to many types of damage and disease. The most common forms of physical damage are closed head injuries such as a blow to the head, a stroke, or poisoning by a wide variety of chemicals that can act as neurotoxins. Infection of the brain is rare because of the barriers that protect it, but is very serious when it occurs. More common are genetically based diseases[citation needed], such as Parkinson's disease, multiple sclerosis, and many others. A number of psychiatric conditions, such as schizophrenia and depression, are widely thought to be caused at least partially by brain dysfunctions, although the nature of such brain anomalies is not well understood.
For more information about Human brain, read the full article at
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News tagged with human brain
Scientists discover 2 genes that drive aggressive brain cancers
Dec 23, 2009 |
5 / 5 (1) |
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A team of Columbia scientists have discovered two genes that, when simultaneously activated, are responsible for the most aggressive forms of human brain cancer.
What is 'Real'? How Our Brain Differentiates Between Reality and Fantasy
Medicine & Health / Neuroscience
Mar 23, 2009 |
4.2 / 5 (22) |
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(PhysOrg.com) -- Most people can easily tell the difference between reality and fantasy. We know that characters in novels and movies are fictitious, and we also understand that historical figures - even if ...
The human brain is on the edge of chaos
Mar 20, 2009 |
4.4 / 5 (35) |
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Cambridge-based researchers provide new evidence that the human brain lives "on the edge of chaos", at a critical transition point between randomness and order. The study, published March 20 in the open-access ...
Brain research shows past experience is invaluable for complex decision making
Medicine & Health / Neuroscience
May 13, 2009 |
3.7 / 5 (3) |
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Researchers funded by the Biotechnology and Biological Sciences Research Council (BBSRC) have shown that past experience really does help when we have to make complex decisions based on uncertain or confusing information. ...
Researchers find that the unexpected is a key to human learning
Medicine & Health / Psychology & Psychiatry
Mar 13, 2009 |
5 / 5 (4) |
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The human brain's sensitivity to unexpected outcomes plays a fundamental role in the ability to adapt and learn new behaviors, according to a new study by a team of psychologists and neuroscientists from the University of ...
Evidence appears to show how and where frontal lobe works
Medicine & Health / Neuroscience
Mar 02, 2009 |
4.7 / 5 (10) |
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(Physorg.com) -- A Brown University study of stroke victims has produced evidence that the frontal lobe of the human brain controls decision-making along a continuum from abstract to concrete, from front to ...
Scientists selectively erase fear memories and gain insight into how the memory works
Medicine & Health / Neuroscience
Mar 12, 2009 |
4.7 / 5 (7) |
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(PhysOrg.com) -- It may sound like something out of a science fiction movie - but bad memories can be erased in mice and this finding sheds light into how memories are normally encoded and stored in the brain. In a study ...
Some Short-term Memories Die Suddenly, No Fading
Medicine & Health / Psychology & Psychiatry
Apr 28, 2009 |
5 / 5 (2) |
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(PhysOrg.com) -- The human brain stores some kinds of memories for a lifetime. But when our eyes are open and looking at things, our gray matter also creates temporary memories that help us process complex ...
Study shows bilinguals are unable to 'turn off' a language completely
Medicine & Health / Psychology & Psychiatry
Aug 18, 2009 |
3.7 / 5 (7) |
5
With a vast majority of the world speaking more than one language, it is no wonder that psychologists are interested in its effect on cognitive functioning. For instance, how does the human brain switch between languages? ...
Brain on a chip?
Technology / Computer Sciences
Mar 16, 2009 |
4.7 / 5 (31) |
2
(PhysOrg.com) -- How does the human brain run itself without any software? Find that out, say European researchers, and a whole new field of neural computing will open up. A prototype 'brain on a chip' is ...
More obesity blues: Obese people are at greater risk for developing Alzheimer's
Medicine & Health / Neuroscience
Aug 25, 2009 |
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0
Obesity is on a rampage, with the World Health Organization pegging the numbers at more than 300 million worldwide, with a billion more overweight. With obesity comes the increased risk for cardiovascular disease, Type II ...
Brain wave patterns can predict blunders, new study finds
Mar 23, 2009 |
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From spilling a cup of coffee to failing to notice a stop sign, everyone makes an occasional error due to lack of attention. Now a team led by a researcher at the University of California, Davis, in collaboration ...
Harvard scientist says we are what we eat -- and what we cook
Jun 01, 2009 |
4.7 / 5 (7) |
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"You are what you eat." Can these pithy words explain the evolution of the human species?
Researchers find new actions of neurochemicals (w/ Video)
Jul 02, 2009 |
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(PhysOrg.com) -- Although the tiny roundworm Caenorhabditis elegans has only 302 neurons in its entire nervous system, studies of this simple animal have significantly advanced our understanding of human ...
Cognitive training can alter the biochemistry of the brain
Feb 06, 2009 |
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(PhysOrg.com) -- Researchers at the Swedish medical university Karolinska Institutet have shown for the first time that the active training of the working memory brings about visible changes in the number of dopamine receptors ...
