The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is located in the head, usually close to the sensory organs for senses such as vision. The brain is the most complex organ in a vertebrate’s body. In a human, the cerebral cortex contains approximately 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.
Physiologically, 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 both by generating patterns of muscle activity and by driving the 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.
The operations of individual brain cells are now understood in considerable detail but the way they cooperate in ensembles of millions is yet to be solved. Recent models in modern neuroscience treat the brain as a biological computer, very different in mechanism from an electronic computer, but similar in the sense that it acquires information from the surrounding world, stores it, and processes it in a variety of ways, analogous to the central processing unit (CPU) in a computer.
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.
The School of Life (@TheSchoolOfLife) tweeted at 5:30 AM – 3 Oct 2016 :
Compensating for the faulty equipment that nature has given us is the task of what we call education and culturehttps://t.co/i52IlyCYfq (http://twitter.com/TheSchoolOfLife/status/782905644928172032?s=17)
Adam Burk (@adamburk) tweeted at 6:01 AM – 19 Sep 2016 :
The Most Depressing Discovery About the Brain, Ever https://t.co/aAnerjaO5w (http://twitter.com/adamburk/status/777839913261727744?s=17)
thinking dangerously in age of normalized ignorance
John Hagel (@jhagel) tweeted at 7:00 AM – 20 Aug 2018 :
New brain research reveals elephants are indeed thoughtful, curious and ponderous creatures with sophisticated cognitive abilities, including social communication, tool construction and use, creative problem-solving, empathy and self-recognition https://t.co/hDa17wwgOU(http://twitter.com/jhagel/status/1031526377139331072?s=17)
cool image of neurons across diff species
dis\order et al
manufactured consent ness
voluntary compliance ness