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
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 ...
Green tea chemical combined with another may hold promise for treatment of brain disorders
Dec 03, 2009 |
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Scientists at Boston Biomedical Research Institute (BBRI) and the University of Pennsylvania have found that combining two chemicals, one of which is the green tea component EGCG, can prevent and destroy a variety of protein ...
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.
Now you see it, now you know you see it
Medicine & Health / Neuroscience
Nov 30, 2009 |
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There is a tiny period of time between the registration of a visual stimulus by the unconscious mind and our conscious recognition of it ― between the time we see an apple and the time we recognize it as an apple. Our ...
Childhood lead exposure causes permanent brain damage
Dec 01, 2009 |
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A study using functional magnetic resonance imaging (fMRI) to evaluate brain function revealed that adults who were exposed to lead as children incur permanent brain injury. The results were presented today at the annual ...
How to read brain activity?
Medicine & Health / Neuroscience
Dec 04, 2009 |
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(PhysOrg.com) -- For the very first time, scientists show what EEG can really tell us about how the brain functions.
Tumor-attacking virus strikes with 'one-two punch'
Dec 01, 2009 |
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Ohio State University cancer researchers have developed a tumor-attacking virus that both kills brain-tumor cells and blocks the growth of new tumor blood vessels.
I see your pain
Medicine & Health / Neuroscience
Dec 03, 2009 |
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(PhysOrg.com) -- How can some sportsmen and women, in the heat of the moment, play on through pain that would floor anyone else? Bert Trautmann, the Manchester City goalkeeper, famously played on through to ...
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 ...
Researchers identify gene that spurs deadly brain cancer
Dec 03, 2009 |
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Howard Hughes Medical Institute (HHMI) researchers have identified a new factor that is necessary for the development of many forms of medulloblastoma, the most common type of malignant childhood brain cancer.
Researchers discover how a brain hormone controls insect metamorphosis
Dec 03, 2009 |
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A team of University of Minnesota researchers have discovered how PTTH, a hormone produced by the brain, controls the metamorphosis of juvenile insects into adults.
New stem cell lines approved for tax-paid research
Dec 02, 2009 |
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(AP) -- Scientists can start using taxpayer dollars to do research with 13 batches of embryonic stem cells and the government says dozens more cell lines should be available soon, opening a new era for the potentially life-saving ...
Discovery makes brain tumor cells more responsive to radiation
Dec 02, 2009 |
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Duke University Medical Center researchers have figured out how stem cells in the malignant brain cancer glioma may be better able to resist radiation therapy. And using a drug to block a particular signaling pathway in these ...
Brain Scan Study Shows Cocaine Abusers Can Control Cravings
Nov 30, 2009 |
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(PhysOrg.com) -- When asked to inhibit their response to a "cocaine-cues" video, active cocaine abusers were, on average, able to suppress activity in brain regions linked to drug craving, according to a new ...
Research sheds new light on epilepsy
Nov 30, 2009 |
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Pioneering research using human brain tissue removed from people suffering from epilepsy has opened the door to new treatments for the disease.
