Early attention selection impairments have been reported in alcoholics and HR (see section on attention – N100 and mismatch negativity), while some studies report no differences. The underlying reason for the variation in results may arise from an enhanced theta phase resetting in the absence of any N1 amplitude and power changes in alcoholics when compared to controls (Fuentemilla et al., 2009). The phase resetting defines excitability windows of phase-locked neurons, which in turn directs information flow, hence implying a hyperexcited neuronal state in alcoholics. Early phase-locked gamma is an important processing step for the selection/identification of target stimuli, indicative of a top-down mechanism involved in selective attention (Fell et al., 2003); it is larger to attended compared to unattended stimuli, particularly over frontal regions (Basar, 1999; Yordanova et al., 2001). Neuroimaging studies using attentional tasks have implicated the role of frontoparietal networks in this top-down control of selective attention (Corbetta et al., 2000; Giesbrecht et al., 2003). Early gamma (28–45 Hz) band response (1–150 ms) is significantly attenuated in the frontal region for target processing in abstinent alcoholics (Padmanabhapillai
