Related topics: brain · genes · brain cells · neurons · neuroscientists

No, the human brain did not shrink 3,000 years ago: research

Did the 12th century B.C.E.—a time when humans were forging great empires and developing new forms of written text—coincide with an evolutionary reduction in brain size? Think again, says a UNLV-led team of researchers ...

Secret language of cells? New cell computations uncovered

Throughout evolution, individual cells have been making successful decisions on their own, even while forming parts of vast networks, such as neurons and glia in the human brain. Now scientists from King Abdullah University ...

Study finds new links between dogs' smell and vision

Cornell University researchers have provided the first documentation that dogs' sense of smell is integrated with their vision and other unique parts of the brain, shedding new light on how dogs experience and navigate the ...

When did genetic variations that make us human emerge?

The study of the genomes of our closest relatives, the Neanderthals and Denisovans, has opened up new research paths that can broaden our understanding of the evolutionary history of Homo sapiens. A study led by the UB has ...

Photonic synapses with low power consumption and high sensitivity

Neuromorphic photonics/electronics is the future of ultralow energy intelligent computing and artificial intelligence (AI). In recent years, inspired by the human brain, artificial neuromorphic devices have attracted extensive ...

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Human brain

The human brain is the center of the human nervous system and is a highly complex organ. Enclosed in the cranium, it has the same general structure as the brains of other mammals, but is over three times as large as the brain of a mammal with an equivalent body size. Most of the expansion comes from the cerebral cortex, a convoluted layer of neural tissue that covers the surface of the forebrain. Especially expanded are the frontal lobes, which are involved in executive functions such as self-control, planning, reasoning, and abstract thought. The portion of the brain devoted to vision is also greatly enlarged in humans.

Brain evolution, from the earliest shrewlike mammals through primates to hominids, is marked by a steady increase in encephalization, or the ratio of brain to body size. The human brain has been estimated to contain 50–100 billion (1011) neurons[citation needed], of which about 10 billion (1010) are cortical pyramidal cells.[citation needed] These cells pass signals to each other via approximately 100 trillion (1014)[citation needed] synaptic connections.

In spite of the fact that it is protected by the thick bones of the skull, suspended in cerebrospinal fluid, and isolated from the bloodstream by the blood-brain barrier, the delicate nature of the human brain makes it susceptible to many types of damage and disease. The most common forms of physical damage are closed head injuries such as a blow to the head, a stroke, or poisoning by a wide variety of chemicals that can act as neurotoxins. Infection of the brain is rare because of the barriers that protect it, but is very serious when it occurs. More common are genetically based diseases[citation needed], such as Parkinson's disease, multiple sclerosis, and many others. A number of psychiatric conditions, such as schizophrenia and depression, are widely thought to be caused at least partially by brain dysfunctions, although the nature of such brain anomalies is not well understood.

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