Lower alpha ERS power in patients was significantly decreased in the right occipital region at 500–750ms (Fig. 4A), and in the right midline parietal and bilateral occipital regions at 750–1000ms (FWE p<0.05) (Fig. 4B). Upper alpha ERS power in patients was significantly decreased in right midline parietal and left occipital regions at 750–1000ms (FWE p<0.05) (Fig. 4C). Recently it was reported that alpha oscillations in the sensorimotor network of monkeys affect discrimination performance by rhythmical inhibition of neural spiking [44]. Decreased ERS in the alpha band may suggest dysfunction in cortical inhibition and discriminating performance by rhythmical inhibition of neural spiking in schizophrenia. Alpha ERD is observed in response to a variety of different types of tasks, and different frequencies of task-related reactivity and topography [57]. Lower (7–10 Hz) and upper (10–13.5 Hz) alpha ERD bands reflect different functions. Lower alpha ERD is topographically widespread over the entire scalp, and its function may be related to general intentional demands; on the other hand, upper ERD is much more topographically restricted and shows a clear relation to semantic processing. Upper alpha ERD has a clear relation to semantic processing demands [36, 39, 51, 53, 54, 57, 58].
