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
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News tagged with brain
Girl's progress after pioneering brain surgery gives hope to other parents
Nov 26, 2009 |
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Lexi Haas is awakening into a world of new possibilities. Miracle by tiny miracle, she is making her body do what she wants -- instead of her body always controlling her. She looked up at her mother a few weeks ago, pursed ...
First anti-seizure drug for newborns to be developed
Medicine & Health / Medications
Nov 26, 2009 |
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(PhysOrg.com) -- Researchers at the UCL Institute for Child Health are developing the first anti-seizure drug specifically for newborn babies, with the aim of reducing brain damage.
Auditory illusion: How our brains can fill in the gaps to create continuous sound
Medicine & Health / Neuroscience
Nov 25, 2009 |
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It is relatively common for listeners to "hear" sounds that are not really there. In fact, it is the brain's ability to reconstruct fragmented sounds that allows us to successfully carry on a conversation in a noisy room. ...
Study sheds light on brain's fear processing center
Nov 25, 2009 |
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Breathing carbon dioxide can trigger panic attacks, but the biological reason for this effect has not been understood. A new study by University of Iowa researchers shows that carbon dioxide increases brain acidity, which ...
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.
fMRI scans used in murder trial sentencing
Nov 25, 2009 |
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(PhysOrg.com) -- Functional Magnetic Resonance Imaging (fMRI) scans have been used, possibly for the first time, in the sentencing phase of a murder trial in Chicago in the US.
Docs say formerly conjoined twins recovering well
Nov 25, 2009 |
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(AP) -- Formerly conjoined twin sisters Trishna and Krishna are enjoying a favorite DVD and trying new foods as they continue their recovery from marathon separation surgery, doctors said.
Comatose for 23 years, Belgian feels reborn
Nov 24, 2009 |
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(AP) -- Helped by a therapist, Rom Houben's outstretched finger tapped with surprising speed on a computer touchscreen, spelling out how he felt "alone, lonely, frustrated" in the 23 years he was trapped ...
'Comfort food' a stress killer: Australian study
Nov 24, 2009 |
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A high-fat, high-sugar diet could have the same effect on brain chemistry as mood-altering drugs, giving scientific support to the craving for "comfort food", Australian researchers said Tuesday.
Road rage: Fuel vapor heightens aggression
Nov 24, 2009 |
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Outrageous prices may not be the only thing causing anger at the petrol pumps. A new study, published in the open access journal BMC Physiology, has shown that rats exposed to fumes from leaded and unleaded gasoline become ...
Measured -- The time it takes us to find the words we need
Medicine & Health / Psychology & Psychiatry
Nov 23, 2009 |
4.1 / 5 (7) |
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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 ...
Upending textbook science on Alzheimer's disease
Medicine & Health / Neuroscience
Nov 23, 2009 |
5 / 5 (6) |
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Alzheimer's disease is caused by the build-up of a brain peptide called amyloid-beta. That's why eliminating the protein has been the focus of almost all drug research pursuing a cure for the devastating neurodegenerative ...
New discovery about the formation of new brain cells
Nov 23, 2009 |
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The generation of new nerve cells in the brain is regulated by a peptide known as C3a, which directly affects the stem cells' maturation into nerve cells and is also important for the migration of new nerve cells through ...
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.
Cancer metabolism discovery uncovers new role of IDH1 gene mutation in brain cancer
Nov 22, 2009 |
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Agios Pharmaceuticals today announced that its scientists have established, for the first time, that the mutated IDH1 gene has a novel enzyme activity consistent with a cancer-causing gene, or oncogene. This breakthrough ...
