Genetics

Neuroscientists pinpoint genes tied to dementia

A UCLA-led research team has identified genetic processes involved in the neurodegeneration that occurs in dementia—an important step on the path toward developing therapies that could slow or halt the course of the disease. ...

Psychology & Psychiatry

The spotlight of attention is more like a strobe

You don't focus as well as you think you do. That's the fundamental finding of a team of researchers from Princeton University and the University of California-Berkeley who studied monkeys and humans and discovered that attention ...

Neuroscience

Birth of new neurons in the human hippocampus ends in childhood

One of the liveliest debates in neuroscience over the past half century surrounds whether the human brain renews itself by producing new neurons throughout life, and whether it may be possible to rejuvenate the brain by boosting ...

Neuroscience

New kinds of brain cells revealed

Under a microscope, it can be hard to tell the difference between any two neurons, the brain cells that store and process information. So scientists have turned to molecular methods to try to identify groups of neurons with ...

Psychology & Psychiatry

Imagine: Our attitudes can change solely by the power of imagination

Sometimes in life there are special places that seem to stand out to us—a school playground, perhaps an old church, or that inconspicuous street corner where you were kissed for the first time. Before the kiss you had never ...

Alzheimer's disease & dementia

Artificial intelligence tool vastly scales up Alzheimer's research

Researchers at UC Davis and UC San Francisco have found a way to teach a computer to precisely detect one of the hallmarks of Alzheimer's disease in human brain tissue, delivering a proof of concept for a machine-learning ...

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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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