New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Human brain

The human brain is the most complex organ in the body and the control center of the nervous system. Weighing about three pounds and composed of approximately 86 billion neurons, it governs every aspect of thought, emotion, behavior, and bodily function. Protected by the skull and suspended in cerebrospinal fluid, the brain processes sensory information, coordinates movement, regulates internal systems, and enables learning, memory, language, and consciousness.

The brain is divided into several major regions, each with specialized roles. The cerebrum, the largest part, is responsible for higher cognitive functions like reasoning, problem-solving, and voluntary movement. It is divided into left and right hemispheres and further into lobes that handle vision, touch, hearing, and decision-making. The cerebellum, located beneath the cerebrum, helps coordinate balance and precise motor control. The brainstem connects the brain to the spinal cord and regulates vital functions such as breathing, heart rate, and sleep.

The brain communicates through a vast network of neurons, which transmit electrical and chemical signals via synapses. Supporting these neurons are glial cells, which provide structural support, nutrition, and protection. This intricate system allows the brain to integrate information from the environment, make decisions, and generate responses in real time.

The human brain is also remarkably adaptable. Through a process called neuroplasticity, it can reorganize itself by forming new neural connections in response to learning, injury, or experience. This adaptability is key to development, recovery, and cognitive flexibility throughout life.

Understanding the brain remains one of science’s greatest challenges. Advances in neuroscience and neuroimaging continue to uncover how the brain functions in health and disease, offering insights into conditions such as Alzheimer’s, Parkinson’s, stroke, epilepsy, and mental illness. As research progresses, the human brain remains both a marvel of biology and a frontier of scientific discovery.

Related Stories
 


Health & Medicine News

February 21, 2026

Researchers tested whether generative AI could handle complex medical datasets as well as human experts. In some cases, the AI matched or outperformed teams that had spent months building prediction models. By generating usable analytical code from ...
A common bacterium best known for causing pneumonia and sinus infections may also play a surprising role in Alzheimer’s disease. Researchers found that Chlamydia pneumoniae can invade the retina and brain, where it sparks inflammation, nerve cell ...
Exercise may sharpen the mind by repairing the brain’s protective shield. Researchers found that physical activity prompts the liver to release an enzyme that removes a harmful protein causing the blood-brain barrier to become leaky with age. In ...
A groundbreaking clinical trial is testing whether specially engineered stem cells can help the brain restore its own dopamine production in people with Parkinson’s disease. Because the condition is driven by the gradual loss of dopamine-producing ...
Breathing polluted air may do more than harm your lungs — it could also increase your risk of Alzheimer’s disease. In a sweeping study of nearly 28 million older Americans, researchers found that ...
A sweeping new study has uncovered a troubling mix of hazardous chemicals in popular hair extensions, including products made from human hair. Researchers detected dozens of substances linked to cancer, hormone disruption, reproductive harm, and ...
A new human study has uncovered how the body naturally turns off inflammation. Researchers found that fat-derived molecules called epoxy-oxylipins rein in immune cells that can otherwise drive chronic disease. Using a drug to boost these molecules ...
A newly discovered bacterial duo may be the hidden cause of chronic constipation. The two microbes break down the colon’s protective mucus layer, leaving stool dry and hard — a problem traditional laxatives don’t fix. Parkinson’s patients, ...
Myopia is skyrocketing around the world, often blamed on endless screen time — but new research suggests the real culprit may be something more subtle. Scientists at SUNY College of Optometry ...
Northwestern researchers have shown that when it comes to cancer vaccines, arrangement can be just as important as ingredients. By repositioning a small fragment of an HPV protein on a DNA-based nanovaccine, the team dramatically strengthened the ...
Sugary drinks may be linked to more than just physical health problems in teens. A new review of multiple studies found a consistent association between high consumption of beverages like soda, energy drinks, sweetened juices, and flavored milks and ...
Intermittent fasting has become one of the most talked-about weight loss trends in recent years, promising dramatic results with simple changes to when you eat. But a major Cochrane review suggests the reality may be far less exciting. After ...

Latest Headlines

updated 12:56 pm ET