The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few invertebrates such as sponges, jellyfish, adult sea squirts and starfish do not have one, even if diffuse neural tissue is present. It is located in the head, usually close to the primary sensory organs for such senses as vision, hearing, balance, taste, and smell. The brain of a vertebrate is the most complex organ of its body. In a typical human the cerebral cortex (the largest part) is estimated to contain 15–33 billion neurons, each connected by synapses to several thousand other neurons. 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 targeting specific recipient cells.Scientists are actively researching operation of our brain, and here are links to some of their research.
From an evolutionary-biological point of view, the function of the brain is to exert centralized control over the other organs of the body. The brain acts on the rest of the body either by generating patterns of muscle activity or by driving secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment. Some basic types of responsiveness such as reflexes can be mediated by the spinal cord or peripheral ganglia, but sophisticated purposeful control of behavior based on complex sensory input requires the information-integrating capabilities of a centralized brain.
From a philosophical point of view, what makes the brain special in comparison to other organs is that it forms the physical structure that generates the mind. As Hippocrates put it: "Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations." In the early part of psychology, the mind was thought to be separate from the brain. However, after early scientists conducted experiments it was determined that the mind was a component of a functioning brain that expressed certain behaviours based on the external environment and the development of the organism. The mechanisms by which brain activity gives rise to consciousness and thought have been very challenging to understand: despite rapid scientific progress, much about how the brain works remains a mystery. The operations of individual brain cells are now understood in considerable detail, but the way they cooperate in ensembles of millions has been very difficult to decipher. The most promising approaches treat the brain as a biological computer, very different in mechanism from electronic computers, but similar in the sense that it acquires information from the surrounding world, stores it, and processes it in a variety of ways.
This article compares the properties of brains across the entire range of animal species, with the greatest attention to vertebrates. It deals with the human brain insofar as it shares the properties of other brains. The ways in which the human brain differs from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because much more can be said about them in a human context. The most important is brain disease and the effects of brain damage, covered in the human brain article because the most common diseases of the human brain either do not show up in other species, or else manifest themselves in different ways.
"Would you put whiskey in your baby's bottle? Drinking during pregnancy is not that much different," she said. "If you ask me if you have three glasses of wine during pregnancy will your child have FASD, I would say probably not. If you ask if there will be changes in the brain, I would say, probably. There is no safe level of drinking during pregnancy."
Growing up in poverty can have long-lasting, negative consequences for a child. But for poor children raised by parents who lack nurturing skills, the effects may be particularly worrisome, according to a new study at Washington University School of Medicine in St. Louis.
Adults with head injuries are known to be at high risk for depression, and yet little research had been done on the topic related to children. In the abstract, "Depression in Children Diagnosed with Brain Injury or Concussion," presented Oct. 25 at the American Academy of Pediatrics (AAP) National Conference and Exhibition in Orlando, researchers sought to identify the prevalence of depression in children with brain injuries, including concussions, in the U.S.
Contrary to common wisdom, an idle brain is in fact doing important work -- and in the age of constant information overload, it's a good idea to go offline on a regular basis, says a researcher from Stockholm's KTH Royal Institute of Technology.
"There are a host of ways exercise has been shown to benefit the brain and reduce the risk of brain diseases," said study author Elinor Ben-Menachem, PhD, MD, with the University of Gothenburg in Sweden and an associate member of the American Academy of Neurology. "This is the first study in humans to show that exercise may also reduce the risk of epilepsy, which can be disabling and life-threatening."
Reversing inflammation in the fluid surrounding the brain's cortex may provide a solution to the complex riddle of Parkinson's, according to researchers who have found a link between pro-inflammatory biomarkers and the severity of symptoms such as fatigue, depression and anxiety in patients with the chronic disease.
"Low testosterone and obesity are common in aging men, and each is associated with type 2 diabetes and Alzheimer's disease," said the study's lead investigator, Anusha Jayaraman, PhD, of the University of Southern California in Los Angeles. "Our new findings demonstrate that obesity and low testosterone combine to not only increase the risk of diabetes but also damage the brain."
The study made use of specialized, baby-friendly magnetic resonance imaging (MRI) to look at the brain growth in a sample of children under the age of 4. The research found that by age 2, babies who had been breastfed exclusively for at least three months had enhanced development in key parts of the brain compared to children who were fed formula exclusively or who were fed a combination of formula and breastmilk. The extra growth was most pronounced in parts of the brain associated with language, emotional function, and cognition, the research showed.
"Problems with memory and thinking are common for people as they get older. Our study shows that on average, problems with memory and thinking may start earlier or get worse more quickly in people who have atrial fibrillation," said study author Evan L. Thacker, PhD, of the University of Alabama at Birmingham. "This means that heart health is an important factor related to brain health."
Smoking increases the risk of heart disease and stroke by five-fold in people under the age of 50 and doubles risk in the over-60s. The protection of children and adolescents from taking up smoking is essential to the future health of Europeans and stronger measures are needed, according to the European Society of Cardiology (ESC). The warning comes on World No Tobacco Day, held today.
UCLA researchers now have the first evidence that bacteria ingested in food can affect brain function in humans. In an early proof-of-concept study of healthy women, they found that women who regularly consumed beneficial bacteria known as probiotics through yogurt showed altered brain function, both while in a resting state and in response to an emotion-recognition task.
While the effects of acute stroke have been widely studied, brain damage during the subacute phase of stroke has been a neglected area of research. Now, a new study by the University of South Florida reports that within a week of a stroke caused by a blood clot in one side of the brain, the opposite side of the brain shows signs of microvascular injury.
Data from 185 research papers revealed, however, that fish oils do not have a direct impact on this process in these areas of the brain, but are likely to play a significant role in stalling refined sugars and saturated fats' ability to inhibit the brain's control on the body's intake of food.
Neuroscientists from Case Western Reserve University School of Medicine and the University of Toronto have developed an efficient and reliable method of analyzing brain activity to detect autism in children. Their findings appear today in the online journal PLOS ONE.
Close family members of people with Alzheimer's disease are more than twice as likely as those without a family history to develop silent buildup of brain plaques associated with Alzheimer's disease, according to researchers at Duke Medicine.
The study results indicated that regular aerobic exercise like walking, running or bicycling is associated with less damage to the brain's "white matter" among heavy alcohol users. White matter, along with gray matter, are the organ's two major physical components. White matter is composed of bundles of nerve cells that act as transmission lines to facilitate communication between various parts of the brain, said lead study author Hollis Karoly, a doctoral student in CU-Boulder's psychology and neuroscience department.