Article Figures & Data
Figures
- Figure 1.
Protocol. Top row, In informative trials (67% of all trials), a one-sided visual cue (200-ms duration) indicated in which ear (left or right) the target sound will be played (100-ms duration) after a fixed 1000-ms delay. Bottom row, In uninformative trials (33% of all trials), a two-sided visual cue (200-ms duration) did not provide any indication in which ear (left or right) the target sound will be played. In 25% of all trials (not depicted in figure), a binaural distracting sound (300-ms duration), such as a phone ring, was played during the delay between cue and target.
- Figure 2.
Mean of median RT (ms) per condition; **p < 0.01. Error bars represent SEM.
- Figure 3.
Comparison between low (7–11 Hz; left panel) and high (11–15 Hz; right panel) α activity. First row, Topographical maps of baseline corrected (−600 to −200 ms pre-cue onset) α power averaged in the respective frequency bands during two latency windows: (1) 200–600 ms and (2) 600–1000 ms, relative to cue onset. Sensors highlighted with black dots present α activities statistically significant from the baseline using cluster-based permutation tests and sensors highlighted by black boxes were used to represent the time-frequency activity in the second row. Second row, Time-frequency representations of α power baseline corrected (−600 to −200 ms pre-cue onset) averaged across sensors highlighted by the black boxes over the topographical maps on the first row. Third row, Distributions of t values, masked at p < 0.05, from cluster-based permutation tests contrasting time-frequency windows of interest against baseline activity at the source level.
- Figure 4.
Source level activity. A, Time course of α (relative to baseline) between 7–11 and 11–15 Hz, for occipital and auditory virtual electrodes averaged across both hemispheres. Note that subtracting the evoked response from single trials before time-frequency transformation only partially removed the evoked response to the target in the α bands. B, Boxplot of Individual α peak frequency in visual and auditory regions. C, Relative power spectrum averaged between 600 and 1000 ms post-cue in visual and auditory regions.
- Figure 5.
α Power (relative to baseline) averaged between 600 and 1000 ms (post-cue onset) at 9 Hz (left panel) and 13 Hz (right panel) for the three cue conditions; *p < 0.05, **p < 0.01. Error bars represent SEM.
- Figure 6.
A, Topography of t values, masked at p < 0.05, from cluster-based permutation testing of the significance of the correlation between α activity (900–1200 ms, 10–15 Hz) and RT at the sensor level. B, Time-frequency distribution of t values, masked at p < 0.05, averaged across sensors highlighted by the black box on the topography in A. C, t values source distributions, masked at p < 0.05, from cluster-based permutation testing of the significance of the correlation between α activity (900–1200 ms, 10–16 Hz) and RT. Please note, that negative t values signify negative correlation between RTs and α activity.
Tables
- Table 1.
Brain regions displaying significant α activity modulations in the low (7–11 Hz) or high (11–15 Hz) α frequency bands in two time windows on baseline contrast in the source level
7–11 Hz Early time window (200–600 ms) Late time window (600–1000 ms) Left and right ↓:
Heschl gyrus
Inferior, middle, and STG calcarine
Cuneus
Inferior, middle, and superior occipital gyri
Inferior parietal gyrus
Postcentral gyrus
Precentral gyrus
Precuneus
Supp. motor areaLeft and right ↓:
Heschl gyrus
Inferior, middle, and STG
Inferior parietal gyrus
Postcentral gyrus
Precentral gyrus
Supp. motor area11–15 Hz Early time window (200–600 ms) Late time window (600–1000 ms) Left and right ↓:
Calcarine
Cuneus
Inferior and middle occipital gyri
Inferior and middle temporal gyriLeft and right ↑:
Calcarine
Cuneus
Precuneus
Inferior and middle occipital gyri
Inferior and middle temporal gyri
Inferior and superior parietal gyriUp-arrows indicate α synchronization (relative increase in power) while down-arrows indicate α desynchronization (relative decrease in power).
- Table 2.
Significant results of the LME model testing the modulation of α activity by cue laterality, hemisphere, and frequency
Factor p value f statistic Hemisphere 0.02 5.3 Frequency <0.001 141 Cue laterality by hemisphere 0.01 4.0 Cue laterality by hemisphere by frequency 0.04 3.1 The interaction of interest is highlighted in bold.
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