Results

Behavioural and Psychological Measures
Subjects’ mean accuracy levels were 99.3% (SD=1.3) and 99.2% (SD=1.4), and their RTs 383.4 ms (SD=75.4) and 381.5 ms (SD=85.4) for the MP and Q-Link+MP conditions respectively. To approximate normality, reaction time data were transformed according to ‘t_RT = natural log (RT)’. There were no condition or condition * time effects for RT (F[1,23]<1.07; p>0.313), and no condition effect for Activation (F[1,23]=0.64; 0.432).

Electrophysiological measures
Resting EEG: To approximate normality, data were transformed according to ‘t_FFT = natural log (FFT)’. Whereas there was a MP-related decrease in delta at right relative to left hemisphere sites, there was a trend-level normalisation of this pattern with the addition of the Q-Link (F[1,23]=3.37; p=0.079; condition * lateral [left versus right]; Fig. 1a). This normalisation did not relate to Activation or RT changes (r[24]<0.26; p>0.264). The MP-related enhancement of alpha over posterior sites was not altered by the Q-Link (F[1,23]=0.25; p=0.620; condition * sagittal [frontal versus posterior]; Fig. 1b), however, the midline alpha increase over time in the MP condition was affected by the Q-Link, with a trend-level reduction over time (F[1,23]=2.95; p=0.099; condition * lateral [lateral versus midline] * time; Fig. 1c). This reduction was related to increased Activation (trend-level; r[24]=-0.42; p=0.052) but not RT (r[24]=0.05; p=0.824). The addition of the Q-Link increased midline gamma (F[1,23]=4.62; p=0.042; condition * laterality [lateral versus midline]), and this increase was inversely related to Activation (trend-level; r[24]=–0.44,p=0.03) but not to RT (r[24]=0.22; p=0.304). This midline gamma increase was largest at fronto-posterior sites (F[1,23]=5.49; p=0.028; condition * lateral [lateral versus midline] * sagittal [central versus fronto-posterior]; Fig. 2a) and this particular pattern was not related to Activation or RT (r[24]<0.26; p>0.218). Gamma increased as a function of exposure duration across the scalp in Q-Link+MP, whereas the MP condition resulted in a reduction at posterior sites (F[1,23]=4.62; p=0.042; condition * sagittal [frontal versus posterior] * time; Fig. 2b), but this difference did not relate to Activation or RT (r[24]<0.02; p>0.910).

Discrimination Task: To approximate normality, data were transformed according to ‘t_ESC = natural log (100-ESC)’, where more positive t_ESC values represent larger neural responses. The addition of the Q-Link attenuated the left hemisphere decrease and enhanced the right hemisphere decrease in evoked delta over time (relative to the MP condition; F[1,23]=14.09; p<0.001; condition * lateral [left versus right] * time; Fig. 2c). This lateralization pattern was inversely related to RT (trend-level; r[24]=–0.41; p=0.048), but not related to Activation (r[24]=0.16; p=0.445). The MP-related attenuation of lateral (relative to midline) theta over time was not significantly affected by the addition of the Q-Link (F[1,23]=1.63; p=0.214; condition * laterality [lateral versus midline] * time; Fig. 1d). The addition of the Q-Link increased left and decreased right hemisphere alpha (F[1,23]=5.02; p=0.035; condition * lateral [left versus right]; Fig. 2d), but this pattern was not related to RT or Activation (r[24]<0.32; p>0.129). The global reduction in evoked beta in the MP condition was also present in Q-Link+MP (F[1,23]=0.01; p=0.977; condition), with an enhanced reduction at midline sites F[1,23]=6.17; p=0.021; condition * lateral [lateral versus midline]). While this MP-related reduction in beta occurred as a function of exposure duration, greatest at frontal and posterior sites, there was a trend-level reduction of this temporal change in the Q-Link+MP condition (F[1,23]=2.07; p=0.164; condition * sagittal [fronto-parietal versus central] * time; Fig. 1e). The addition of the Q-Link caused a marked global decrease in evoked gamma (F[1,23]=9.58; p=0.005; condition; see Fig. 4) that was greatest at lateral (F[1,23]=8.39; p=0.008; condition * lateral [midline versus lateral]) and lateral posterior sites. This reduced the MP-related gamma enhancement at frontal midline and lateral posterior sites (F[1,23]=6.65; p=0.017; condition * lateral [midline versus lateral] * sagittal [front versus posterior]; Fig. 1f). The gamma decrease at left hemisphere sites increased over time (F[1,23]=4.55; p=0.044; condition * lateral [left versus right] * time). None of the gamma patterns were related to RT or Activation (r[24]<0.25; p>0.240).

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