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Transcript:
Nerve cells, or neurons, are the building blocks of the nervous system. They pass information in the form of electrochemical impulses 'fired' across the synapse - the gap at the junction between neurons. These electrochemical signals excite or inhibit the receiving neurons, 'instructing' them whether or not to fire and pass on a message. This selective transmission of information sets up distinctive channels of communication, neural pathways, that together form a complex neural network. Some 80 per cent of the 100 billion or so neurons in the human body are in the brain itself, allowing countless different neural pathways. The brain's various functions -- sensory experiences, coordination and movement, and 'higher functions', such as perception, language and reasoning - each show particular pattern of neural activity across different areas of the brain. Only recently have brain-imaging techniques allowed neuroscientists to examine this activity in detail and it has become obvious that we still have a lot to learn about its complexity.