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.
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News tagged with brain
Neuroscientists uncover possible basis of short-term memory
Medicine & Health / Neuroscience
16 hours ago |
4.8 / 5 (15) |
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, ...
Wiggling and waggling: Study sheds light on amazing bee brain
Dec 21, 2009 |
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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.
Researchers crack part of the neuronal code
Medicine & Health / Neuroscience
Dec 22, 2009 |
4.9 / 5 (7) |
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(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) |
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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.
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 ...
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 ...
Canadian police consider GPS for people with Alzheimer's
Electronics / Consumer & Gadgets
Dec 23, 2009 |
4 / 5 (2) |
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Police in Montreal are studying the possibility of offering GPS bracelets to people suffering from Alzheimer's disease, an official told AFP.
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.
Fish fatty acids don’t make you cleverer or happier
Dec 22, 2009 |
3.5 / 5 (2) |
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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 ...
Protein link may be key to new treatment for aggressive brain tumor
Dec 22, 2009 |
5 / 5 (1) |
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Biomedical researchers at the University of Central Florida have found a protein that could hold the key to treating one of the most common and aggressive brain tumors in adults.
Dutch researchers explore advanced brain diagnostic techniques
Medicine & Health / Neuroscience
Dec 21, 2009 |
4 / 5 (1) |
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At present the task of diagnosing brain disorders using electroencephalography (EEG) is still performed by humans, but in years to come it will increasingly be taken over by computerized systems. This will ...
