Power Time Curves. Z-transformed wavelet power in the θ, α, β, and γ frequency bands are illustrated in the parietal brain region (from electrode Pz) for 12 subjects. The fixation asterisk appeared at t = 0 sec, as indicated by the vertical dashed line. The 3 study items appeared at average times of 1.2 sec, 2.2 sec, and 3.2 sec as indicated by vertical dotted lines. The retention interval started at average time t = 3.9 sec. The probe item appeared at average time t = 4.4 sec (vertical dotted line), and the response was made on average at t = 5 sec (vertical dashed line). The first row illustrates power for each of the five stimulus pools. The second and third rows illustrate power in the verbal-vs-grating and in the verbal-vs-spatial tasks, respectively. Verbal refers to the mean power from the letter, word, and object tasks. Significant differences between verbal and each of the nonverbal tasks (t(11) = 2.2, p < 0.05) are denoted by a thick horizontal bar at the bottom of each panel in the second and third rows.