FIGURE 1. Investigating sensory processing with discrete versus continuous stimuli.

(A) An EEG experiment involving listening to individual syllables that are presented sequentially. The discrete syllable timestamps can be used to epoch the data. (B) An EEG experiment involving natural speech listening. The stimulus was continuous speech, hence there is no isolated, discrete event in the traditional experimental sense that can be used to epoch the data. (C) A continuous experimental stream is rich in information and can be described using both continuous and discrete features. Some stimulus features are encoded continuously by the brain so the feature of interest is continuous in both time and magnitude, such as the sound envelope (top panel). Events of interest in the continuous stream can be described using discrete timestamps. For example, phonemic surprisal describes the level of unexpectedness of each phoneme based on the preceding context (middle panel). Additionally, a binary mask can be used to indicate discrete events over the continuous experiment, such as phoneme onsets (third panel).