Related topics: neurons , proceedings of the national academy of sciences , brain cells , brain activity , 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
Seeing without looking
Medicine & Health / Neuroscience
Dec 28, 2009 |
4.6 / 5 (13) |
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Like a spotlight that illuminates an otherwise dark scene, attention brings to mind specific details of our environment while shutting others out. A new study by researchers at the Salk Institute for Biological ...
Schizophrenia mouse model should improve understanding and treatment of the disorder
Dec 28, 2009 |
4 / 5 (4) |
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Scientists have created what appears to be a schizophrenic mouse by reducing the inhibition of brain cells involved in complex reasoning and decisions about appropriate social behavior.
Neuroscientists uncover possible basis of short-term memory
Medicine & Health / Neuroscience
Dec 27, 2009 |
4.8 / 5 (17) |
0
Ben W. Strowbridge, PhD, associate professor of neuroscience and physiology/biophysics, and Phillip Larimer, PhD, a MD/PhD student in the neurosciences graduate program at Case Western Reserve University School of Medicine, ...
Small molecules found to protect cells in multiple models of Parkinson's disease
Dec 28, 2009 |
not rated yet |
0
Several structurally similar small molecules appear capable of protecting cells from alpha-synuclein toxicity in multiple models of Parkinson's disease, according to Whitehead Institute researchers. Misfolded copies of the ...
Wiggling and waggling: Study sheds light on amazing bee brain
Dec 21, 2009 |
4.4 / 5 (10) |
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(PhysOrg.com) -- Their brains are tiny - about the size of sesame seeds - and yet the behaviour of the humble honey bee is so advanced it has scientists scratching their heads in disbelief.
Scientists discover 2 genes that drive aggressive brain cancers
Dec 23, 2009 |
4 / 5 (2) |
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A team of Columbia scientists have discovered two genes that, when simultaneously activated, are responsible for the most aggressive forms of human brain cancer.
Why newborn babies can't walk
Medicine & Health / Neuroscience
Dec 18, 2009 |
4.2 / 5 (13) |
16
(PhysOrg.com) -- The first steps of an infant is a real milestone in the development of all mammals including humans, but little is known about why some animals can walk soon after birth, while others need ...
Researchers crack part of the neuronal code
Medicine & Health / Neuroscience
Dec 22, 2009 |
4.9 / 5 (7) |
0
(PhysOrg.com) -- Prostheses for paralysed patients, communication with patients who have lost all capacity for normal communication - the hopes for modern brain research are high. However, such brain-machine ...
Depression saps endurance of the brain's reward circuitry
Medicine & Health / Neuroscience
Dec 21, 2009 |
4.5 / 5 (6) |
1
A new study at the University of Wisconsin-Madison suggests that depressed patients are unable to sustain activity in brain areas related to positive emotion.
Microcephaly genes associated with human brain size
Dec 21, 2009 |
3.7 / 5 (3) |
1
A group of Norwegian and American researchers have shown that common variations in genes associated with microcephaly - a neuro-developmental disorder in which brain size is dramatically reduced - may explain differences ...
Researchers show brain waves can 'write' on a computer in early tests
Dec 07, 2009 |
4.9 / 5 (18) |
3
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, ...
Canadian police consider GPS for people with Alzheimer's
Electronics / Consumer & Gadgets
Dec 23, 2009 |
4 / 5 (2) |
1
Police in Montreal are studying the possibility of offering GPS bracelets to people suffering from Alzheimer's disease, an official told AFP.
Subtle change dramatically reduces pathogenic potential of Huntington's protein
Dec 23, 2009 |
not rated yet |
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Scientists have identified a key molecular switch that may drive the onset of Huntington's disease (HD), an incurable neurodegenerative disorder that leads to severe disruptions in muscle coordination and cognitive function. ...
We now know that the brain controls the formation of bone
Dec 22, 2009 |
5 / 5 (5) |
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The brain acts as a profound regulatory centre, controlling myriad processes throughout the body in ways we are only just beginning to understand. In new findings, Australian scientists have shown surprising connections between ...
Fish fatty acids don’t make you cleverer or happier
Dec 22, 2009 |
3.3 / 5 (3) |
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(PhysOrg.com) -- A diet rich in fish fatty acids has no effect on cognitive functions such as memory and concentration in the elderly. Nor does it affect their level of wellbeing. This is the conclusion drawn by Dutch researcher ...
