Fig. 1.

Schematic representation of the stimuli. Experiment 1 (A) consisted of isochronous sequences with one of 3 IOI durations (75, 125 or 225 ms). Experiment 2 contained two types of stimuli: Regular sequences, consisting of a sequential repetition of the 3 IOIs (B), and random sequences (C) where the IOIs were presented in random order. Experiment 3 consisted of the same regular sequences as in Experiment 2 except that these contained occasional frequency deviants which listeners were instructed to detect (D). The sequences were interrupted after a variable duration and brain responses were grouped for analysis according to the IOI expected after sequence interruption. The sequences plotted, save for the random sequence in C, are conditions where the expected IOI, if listeners are able to learn the temporal structure, is 75 ms. The dashed line marks the time of the next expected tone pip.