As illustrated in Fig. 5b, the alcoholic group displayed lower power compared to controls in all frequency bands at all time-points for the Go as well as NoGo conditions at midline frontocentral location (refer to respective TFR plots). Further, 2D surface Laplacian head-maps showed that although both groups had evoked slow alpha power density localized bilaterally at parieto-occipito-temporal regions of the brain, the alcoholics displayed much lower and region-restricted density compared to the controls for both task conditions. In addition, only control group displayed higher density of evoked slow alpha for the NoGo (left bottom panel) compared to the Go (left top panel) task condition at frontocentral midline region. Furthermore, although alcoholic did not show evoked slow alpha density at frontocentral regions for either task condition as illustrated (Fig. 5b; rightmost column), they displayed significantly more evoked slow alpha power compared to the Go condition at frontocentral regions (Fig 5a top right panel). It is interesting to note that despite higher density of the evoked slow alpha shown posteriorly, group differences on evoked slow alpha power were statistically significant at centroparietal regions for the Go and central regions for the NoGo task conditions.
