Neurons in The Brain
The number of neurons in the brain varies dramatically from species to species. One estimate puts the human brain at about 100 billion (1011) neurons and 100 trillion (1014) synapses. Another estimate is 86 billion neurons, of which 16.3 billion are in the cerebral cortex, and 69 billion in the cerebellum. By contrast, the nematode worm Caenorhabditis elegans has just 302 neurons making it an ideal experimental subject as scientists have been able to map all of the organism's neurons. The fruit fly Drosophila melanogaster, a common subject in biological experiments, has around 100,000 neurons and exhibits many complex behaviors. Many properties of neurons, from the type of neurotransmitters used to ion channel composition, are maintained across species, allowing scientists to study processes occurring in more complex organisms in much simpler experimental systems.
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Famous quotes containing the word brain:
“I don’t know but a book in a man’s brain is better off than a book bound in calf—at any rate it is safer from criticism. And taking a book off the brain, is akin to the ticklish & dangerous business of taking an old painting off a panel—you have to scrape off the whole brain in order to get at it with due safety—& even then, the painting may not be worth the trouble.”
—Herman Melville (1819–1891)