Alzheimer's disease & dementia

Risk and progression of Alzheimer's disease differ by sex

The abnormal accumulation of proteins in the brain is a biological marker for Alzheimer's disease, but the ways in which these proteins spread may help explain why the prevalence of Alzheimer's is higher in women than in ...

Health

Wearing hearing aid may help protect brain in later life

A new study has concluded that people who wear a hearing aid for age-related hearing problems maintain better brain function over time than those who do not. It builds on important research in recent years pulled together ...

Alzheimer's disease & dementia

Scientists close in on blood test for Alzheimer's

Scientists are closing in on a long-sought goal—a blood test to screen people for possible signs of Alzheimer's disease and other forms of dementia.

Neuroscience

Reducing seizures by removing newborn neurons

Removing new neurons born after a brain injury reduces seizures in mice, according to new research in JNeurosci. This approach could potentially help prevent post-injury epilepsy.

Health

Dance your way to better health

(HealthDay)—Two very different studies show that dancing is more than just fun. It can keep your mind sharp and your heart healthy.

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Brain

The 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.

This text uses material from Wikipedia, licensed under CC BY-SA