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 ...
Computer Based on Insights From The Brain Moves Closer to Reality
Technology / Computer Sciences
Nov 18, 2009 |
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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, ...
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, ...
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.
New study shows brain's ability to reorganize
Medicine & Health / Neuroscience
Nov 18, 2009 |
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(PhysOrg.com) -- Visually impaired people appear to be fearless, navigating busy sidewalks and crosswalks, safely finding their way using nothing more than a cane as a guide. The reason they can do this, researchers suggest, ...
Antidepressant Can Change Patient's Personality
Medicine & Health / Psychology & Psychiatry
Dec 07, 2009 |
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(PhysOrg.com) -- The nation is still debating the effects of antidepressant medications on brain chemistry almost 20 years after publication of the best-seller "Listening to Prozac." Though selective serotonin reuptake inhibitors ...
Pilot study relates phthalate exposure to less-masculine play by boys
Nov 16, 2009 |
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A study of 145 preschool children reports, for the first time, that when the concentrations of two common phthalates in mothers' prenatal urine are elevated their sons are less likely to play with male-typical toys and games, ...
Research backs theory on autism, schizophrenia
Nov 30, 2009 |
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(PhysOrg.com) -- New research by Simon Fraser University evolutionary biologist Bernard Crespi reinforces his theory that autism and schizophrenia are diametric or opposite conditions based on genes.
Scientists discover first evidence of brain rewiring in children
Medicine & Health / Neuroscience
Dec 09, 2009 |
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Carnegie Mellon University scientists Timothy Keller and Marcel Just have uncovered the first evidence that intensive instruction to improve reading skills in young children causes the brain to physically ...
Two molecules affecting brain plasticity
Medicine & Health / Neuroscience
Nov 25, 2009 |
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(PhysOrg.com) -- You wouldn't want a car with no brakes. It turns out that the developing brain needs them, too.
Birds 'See' Earth's Magnetic Field
Nov 16, 2009 |
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When birds migrate over long distances -- sometimes thousands of miles -- they usually end up in exactly the same place year after year. Such accurate feats of navigation, accomplished by millions of birds ...
Measured -- The time it takes us to find the words we need
Medicine & Health / Psychology & Psychiatry
Nov 23, 2009 |
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(PhysOrg.com) -- The time it takes for our brains to search for and retrieve the word we want to say has been measured for the first time. The discovery is reported in a paper published in the Proceedings of the National Ac ...
Study shows new brain connections form rapidly during motor learning
Medicine & Health / Neuroscience
Nov 29, 2009 |
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(PhysOrg.com) -- New connections begin to form between brain cells almost immediately as animals learn a new task, according to a study published this week in Nature. Led by researchers at the University of Cal ...
The Queen and I: How autistic brain distinguishes oneself from others
Medicine & Health / Neuroscience
19 hours ago |
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Scientists at the University of Cambridge have discovered that the brains of individuals with autism are less active when engaged in self-reflective thought. The study published today in the journal Brain provid ...
