Fig. 1.

Grand average time-frequency maps summarize 25 Study 1 subjects and three, separate test occasions at electrode Fz. Evoked power (left column), phase-locking factor (middle column), and total power (right column) were estimated from EEG data collected during 20-Hz (top row), 30-Hz (middle row), and 40-Hz auditory steady state stimulation. EEG frequency, in Hertz (Hz), is shown on the y-axis and time, in milliseconds (ms), is shown on the x-axis, with horizontal dashed white lines indicating the frequency of the steady-state stimulation. Darker red colors indicate greater auditory steady-state responses.