Electroencephalogram (EEG) has the greatest temporal resolution among various non-invasive techniques for studying human brain functions. EEG reflects the sum of activities of a large number of neurons interacting dynamically in network.

Sensory, motor, or cognitive events modulates the on-going EEG, the small amplitude change of which can be observed as evoked potential (EP) or event-related potential (ERP) by the method of time-locked averaging. We use this technique to investigate the neural substrates of higher brain functions such as music and language (Refs 1–4).

Fig 1.

Possessors and non-possessors of absolute pitch (AP) were presented with pure tones. In listeners with AP, passive listening to the stimuli elicited a unique negativity over left posterior temporal scalp (AP negativity, arrow), at a relatively short latency of 150 msec (Ref. 1). The result suggests a close functional relationship between AP and language.