The Human Brain

The human brain is arguably the most complex structure in the known universe. Weighing about 1.4 kg and containing approximately 86 billion neurons connected by 100 trillion synapses, it is responsible for everything that makes us human — consciousness, language, creativity, emotion, and self-awareness. The brain consumes 20% of the body's energy despite comprising only 2% of its weight. It generates about 12-25 watts of electricity — enough to power a low-wattage LED bulb. It processes about 120 bits of information per second during normal waking consciousness. Neuroscience is still in its infancy — we understand less about the brain than about distant galaxies. The "hard problem of consciousness" — why and how subjective experience arises from neural activity — remains one of the deepest unsolved problems in science. The Human Connectome Project aims to map every connection in the human brain. The result will be a graph of staggering complexity — the functional equivalent of every road, path, and bridge on Earth.