Genetics

Discovery gives insight into brain function, breakdowns

Scientists at Oregon Health & Science University have identified a long-sought gene-encoded protein that enables the brain to communicate a broad range of signals across gaps between neurons, known as synapses. The discovery ...

Neuroscience

Strategies to generate neuronal diversity

The complexity and function of the nervous system relies on the generation of unparalleled neuronal diversity across molecular, morphological, functional and connectional features throughout developmental continuum. However, ...

Neuroscience

A new window into the brain's computational function

The function of the human brain is exceptional, driving all aspects of our thoughts and creativity. Yet the part of the human brain—the neocortex—responsible for such cognitive functions has a similar overall structure ...

Neuroscience

Helping the body and brain welcome bionic limbs and implants

Not that long ago, the concept of the bionic human seemed far-fetched, but wearable robotic suits, brain-controlled extra limbs and mind-operated wheelchairs are now under active development. They bring the dream of human-machine ...

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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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