Neuroscience Brain

The human brain contains approximately 86 billion neurons connected by 100 trillion synapses — processing 400 billion bits of information per second while consuming only 20 watts (less than a dim light bulb). It is the most complex known object in the universe — and it studies itself, which is both remarkable and constraining. Major neuroscience discoveries: the neuron doctrine (Santiago Ramón y Cajal, 1880s — neurons are distinct cells, not a continuous network); split-brain experiments (Roger Sperry, 1960s — left and right hemispheres have different functions); long-term potentiation (the mechanism of memory formation); neuroplasticity (the brain can reorganize itself throughout life); default mode network (the brain is highly active at 'rest', running simulations and planning). The 'hard problem of consciousness' — why physical brain processes give rise to subjective experience — remains unsolved.