Fig. 5.

Light strengthens the relationship between EEG θ/γ power and performance. Scatter plots show the relationships between θ/γ power and recognition performance under the different lighting conditions (blue, 5 lx; green, 50 lx; and red, 500 lx; coloured lines, least-square linear regression fits) in the 5 implanted mice. EEG spectra (in μV² per 0.25 Hz) during sample and test phases were expressed as a percentage of the EEG spectrum (in μV² per 0.25 Hz) in the corresponding frequency bins during the baseline period. In each panel, there are 30 data points (5 mice × 2 types of stimulus × 3 light intensities). Panel A shows strengthening of the effect of sample EEG θ power on recognition memory performance when light intensity was increased from 5 and 50 lx to 500 lx (Light × θ Power interaction in the linear mixed-effects model); panel B shows the statistically nonsignificant effect of test θ power on performance; panel C shows the nonsignificant effect of sample γ power on performance; and panel D shows strengthening of the effect of test γ power on performance when light intensity was increased from 5 lx to 50 and 500 lx (Light × γ Power interaction in the linear mixed-effects model).