Related topics: brain activity , proceedings of the national academy of sciences , stroke , dopamine , nerve cells
Brain
hideThe brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all. In vertebrates, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, balance, taste, and smell.
Brains can be extremely complex. The cerebral cortex of the human brain contains roughly 15-33 billion neurons depending on gender and age, linked with up to 10,000 synaptic connections each. Each cubic millimeter of cerebral cortex contains roughly one billion synapses. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body and target them to specific recipient cells.
The most important biological function of the brain is to generate behaviors that promote the welfare of an animal. Brains control behavior either by activating muscles, or by causing secretion of chemicals such as hormones. Even single-celled organisms may be capable of extracting information from the environment and acting in response to it. Sponges, which lack a central nervous system, are capable of coordinated body contractions and even locomotion. In vertebrates, the spinal cord by itself contains neural circuitry capable of generating reflex responses as well as simple motor patterns such as swimming or walking. However, sophisticated control of behavior on the basis of complex sensory input requires the information-integrating capabilities of a centralized brain.
Despite rapid scientific progress, much about how brains work remains a mystery. The operations of individual neurons and synapses are now understood in considerable detail, but the way they cooperate in ensembles of thousands or millions has been very difficult to decipher. Methods of observation such as EEG recording and functional brain imaging tell us that brain operations are highly organized, but these methods do not have the resolution to reveal the activity of individual neurons.
For more information about Brain, read the full article at
Wikipedia.
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News tagged with brain
Intel wants a chip implant in your brain
Nov 23, 2009 |
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(PhysOrg.com) -- Computer chip maker Intel wants to implant a brain-sensing chip directly into the brains of its customers to allow them to operate computers and other devices without moving a muscle.
Mathematical model of a simple circuit in a chicken brain raises fundamental questions
Dec 01, 2009 |
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(PhysOrg.com) -- The Web site Neuroanthropology asks visitors to complete this quote, "One of the difficulties in understanding the brain is ...". In addition to the typical facetious remarks, such as "so ...
You can control your Marilyn Monroe neuron
Medicine & Health / Neuroscience
Oct 22, 2009 |
4.7 / 5 (26) |
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(PhysOrg.com) -- In a scientific first, researchers have been able to demonstrate the ability of humans to control the activity of individual brain cells.
Why antidepressants don't work for so many
Medicine & Health / Psychology & Psychiatry
Oct 23, 2009 |
5 / 5 (24) |
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More than half the people who take antidepressants for depression never get relief. Why? Because the cause of depression has been oversimplified and drugs designed to treat it aim at the wrong target, according to new research ...
Computer Based on Insights From The Brain Moves Closer to Reality
Technology / Computer Sciences
Nov 18, 2009 |
4.6 / 5 (24) |
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(PhysOrg.com) -- Today at SC 09, the supercomputing conference, IBM announced significant progress toward creating a computer system that simulates and emulates the brain's abilities for sensation, perception, ...
WHO study suggests link between cell phones and tumors
Oct 27, 2009 |
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(PhysOrg.com) -- Preliminary results of an International investigation by the World Health Organization (WHO) suggest there may be a "significantly increased risk" of some types of brain tumors after use of ...
Researchers document how brain computes language
Medicine & Health / Neuroscience
Oct 15, 2009 |
4.9 / 5 (19) |
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A study by researchers at the University of California, San Diego School of Medicine reports a significant breakthrough in explaining gaps in scientists' understanding of human brain function. The study - ...
Bigger not necessarily better, when it comes to brains
Nov 17, 2009 |
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(PhysOrg.com) -- Tiny insects could be as intelligent as much bigger animals, despite only having a brain the size of a pinhead, say scientists at Queen Mary, University of London.
Researchers show brain waves can 'write' on a computer in early tests
Dec 07, 2009 |
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Neuroscientists at the Mayo Clinic campus in Jacksonville, Fla., have demonstrated how brain waves can be used to type alphanumerical characters on a computer screen. By merely focusing on the "q" in a matrix of letters, ...
Scientists remove amyloid plaques from brains of live animals with Alzheimer's disease
Oct 15, 2009 |
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A breakthrough discovery by scientists from the Mayo Clinic in Jacksonville, FL, may lead to a new treatment for Alzheimer's Disease that actually removes amyloid plaques -- considered a hallmark of the disease -- from patients' ...
Alzheimer's researchers find high protein diet shrinks brain
Medicine & Health / Neuroscience
Oct 20, 2009 |
4.7 / 5 (15) |
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One of the many reasons to pick a low-calorie, low-fat diet rich in vegetables, fruits, and fish is that a host of epidemiological studies have suggested that such a diet may delay the onset or slow the progression of Alzheimer's ...
Smart rat 'Hobbie-J' produced by over-expressing a gene that helps brain cells communicate
Oct 19, 2009 |
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Over-expressing a gene that lets brain cells communicate just a fraction of a second longer makes a smarter rat, report researchers from the Medical College of Georgia and East China Normal University.
Scientists give flies false memories
Medicine & Health / Neuroscience
Oct 15, 2009 |
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By directly manipulating the activity of individual neurons, scientists have given flies memories of a bad experience they never really had, according to a report in the October 16th issue of the journal Cell.
Why can't chimps speak? Study links evolution of single gene to human capacity for language
Nov 11, 2009 |
3.9 / 5 (15) |
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(PhysOrg.com) -- If humans are genetically related to chimps, why did our brains develop the innate ability for language and speech while theirs did not?
Manipulating brain inflammation may help clear brain of amyloid plaques
Medicine & Health / Neuroscience
Oct 22, 2009 |
4.8 / 5 (12) |
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In a surprising reversal of long-standing scientific belief, researchers at the Mayo Clinic campus in Florida have discovered that inflammation in the brain is not the trigger that leads to buildup of amyloid deposits and ...
