Introduction Footnotes

1. The nervous system (including the brain) consists of cells, neurons, that have an elongated part (axon) and connect to other neurons through structures called synapses. Under certain conditions a neuron becomes "excited" transmitting an electric wave called action potential. When displayed on an oscilloscope the wave has the form of a spike that has a fixed size for a given preparation. The fact that a neuron can have only one of two states (quite or transmitting a spike of fixed size) led some people to think about parallels between computers and brains. It turns out that while the spike of the action potential has a fixed amplitude, a neuron may fire several of them so that time between spikes seems to be an important carrier of information and that is certainly not binary. Back to the Introduction