But for the past half century, neuroscientists have generally supposed that the process by which the brain achieves its phenomenal performance is fundamentally similar to the way electronic computers work. Supercomputers are likewise built of millions of interlinked simple switches, consisting of transistors on silicon chips by companies such as Intel. Recent research is forcing a re-evaluation of this standard model. The organ of thought is looking far more complex than scientists believed just a few years ago. Koch's conclusions are based on studies of the precise electrical behavior of cells in the brain.
Neurons conduct signals in the form of tiny electrical impulses, known as spikes.
How and when synapses relay messages between neurons is crucially important in controlling mental activity. Moreover, neuroscientists believe that learning occurs through a change in the strength of certain synaptic connections. A frequently-used synapse becomes stronger, whereas an infrequently used one may grow weaker over time. Researchers have long understood the basic division of function in the neuron. In the traditional view of the neuron, which goes back to experiments conducted in the 1940s, the cell functions as a fairly simple on-off switch.