, 2002), and ADHD patients show greater frontal and parietal alpha EEG power (8–10 Hz) during a sustained attention task (Loo et al., 2009). Considering

that bright light plays a therapeutic role in ADHD (Gruber et al., 2007) and schizophrenia (Aichhorn et al., 2007), AZD2014 lighting conditions seem to modulate human attentional processing. Therefore, it is important to understand how illumination influences attentional processing and cognitive performance. Among the various aspects of attention, we selected sustained attention to assess under specific combinations of illumination parameters. We supposed that a stationary illumination condition might affect a sustained mental state, so sustained attention was considered to be one of the appropriate targets to investigate possible influences by background illumination. Sustained attention, the GSK2118436 ic50 capability to maintain the focus of attention over time (Mirsky et al., 1991), can be generally assessed, using the continuous performance test (CPT; Riccio et al., 2001), which is featured by a rapid presentation of continuously changing stimuli with an infrequently occurring target stimulus. Several studies have evaluated different aspects of EEG activity recorded during sustained attention tasks.

Since ongoing tonic alpha activity has been reported to be associated with the sustained attention processing (Dockree et al., 2007 and Orekhova Vitamin B12 et al., 2001), we focused on the analysis of EEG alpha activity related to sustained attention task-performance under different illumination conditions. Because lower prestimulus alpha power facilitates task-performance (Ergenoglu et al., 2004 and Hanslmayr et al., 2007), we investigated whether background illumination conditions can affect the prestimulus alpha activity level, which reflects prestimulus preparatory mental states for the sustained and selective allocation of neural processing

resources to target information. In particular, neural activity related to sustained attentional processing has been reported in the parietal brain region (Lee et al., 2013 and Thakral and Slotnick, 2009). Therefore, we hypothesized that light conditions would modulate alpha activity in the parietal region during a sustained attention task. For example, it was suggested that parietal alpha synchronization reflects an active inhibition of certain parietal networks involved in maintaining attention to peripheral visual field (Orekhova et al., 2001), and that parietal alpha activity ipsilateral to the attended hemi-field was enhanced relative to the control condition when attention was shifted away from fixation (Cosmelli et al., 2011). Moreover, we hypothesized that the background illumination condition would affect selective sensory gain control in the visual pathways.