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.
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News tagged with human brain
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 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 ...
Human brains pay a price for being big
Biology /
Aug 05, 2008 |
4.4 / 5 (32) |
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Metabolic changes responsible for the evolution of our unique cognitive abilities indicate that the brain may have been pushed to the limit of its capabilities. Research published today in BioMed Central's open access journal ...
1 sleepless night increases dopamine in the human brain
Aug 19, 2008 |
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Just one night without sleep can increase the amount of the chemical dopamine in the human brain, according to new imaging research in the August 20 issue of The Journal of Neuroscience. Because drugs that increase dopami ...
Researchers discover new mechanism for attentional control in the human brain
Dec 15, 2008 |
4.6 / 5 (25) |
1
A study by UC Davis researchers appearing in the journal Science reports the discovery of a new mechanism of attention in the human brain. Previous studies in animals implicated changes in the state of a portion of the br ...
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 ...
Researchers identified a protein essential in long term memory consolidation
Sep 09, 2008 |
4.6 / 5 (14) |
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New research at the University of Haifa identified a specific protein essential for the process of long term memory consolidation. This is the latest of several discoveries that are leading us towards a better understanding ...
New map IDs the core of the human brain
Jul 01, 2008 |
4.4 / 5 (14) |
1
An international team of researchers has created the first complete high-resolution map of how millions of neural fibers in the human cerebral cortex -- the outer layer of the brain responsible for higher ...
Cognitive training can alter the biochemistry of the brain
Feb 06, 2009 |
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1
(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 ...
The Vision Revolution: Eyes Are the Source of Human 'Superpowers'
Medicine & Health / Neuroscience
Jul 03, 2009 |
2.8 / 5 (18) |
20
For Mark Changizi, it’s all in the eyes.
What It's Like to Be a Bat
Biology /
Jun 26, 2008 |
3.8 / 5 (13) |
0
Not many people think about what it's like to be a bat, but for those who do, it's enlightening and potentially groundbreaking for understanding aspects of the human brain and nervous system.
Evidence appears to show how and where frontal lobe works
Medicine & Health / Neuroscience
Mar 02, 2009 |
4.7 / 5 (10) |
0
(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 ...
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 ...
High population density triggers cultural explosions
Other Sciences / Social Sciences
Jun 04, 2009 |
4.8 / 5 (8) |
3
Increasing population density, rather than boosts in human brain power, appears to have catalysed the emergence of modern human behaviour, according to a new study by UCL (University College London) scientists published in ...
New research identifies key contributor to Alzheimer's disease process
Nov 14, 2008 |
4.1 / 5 (8) |
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Walter J. Lukiw, PhD, Associate Professor of Neuroscience and Ophthalmology at LSU Health Sciences Center New Orleans, is the lead author of a paper identifying, for the first time, a specific function of a fragment of ribonucleic ...
