The pair of electrodes measures the difference in electrical potential (voltage) between their two positions above the brain.

这对电极测的是大脑上两点间的电位差。

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In the brain, the signals travelling through the synapses rely on action potential, which is the electrical energy created by the difference in concentrations of charged atoms (ions) on the inside and outside of neuron, which move back and forth through ion channels.

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