COGNITIVE NEUROSCIENCE AND NEUROPSYCHOLOGYAlpha reduction and event-related potentials, theta and gamma increase linked to letter selectionDigiacomo, Marcia R.; Gómez, Carlos M.; Flores, Angélica B.Author Information Department of Experimental Psychology, University of Seville, Spain Correspondence to Dr Carlos M. Gómez, Dept. de Psicología Experimental, Facultad de Psicología, c/Camilo José Cela s/n, Sevilla 41018, Spain Tel: +954557800; fax: +954551784; e-mail: [email protected] Received 15 January 2007; accepted 23 January 2007 NeuroReport: May 28, 2007 - Volume 18 - Issue 8 - p 729-733 doi: 10.1097/WNR.0b013e3280c1e370 Buy Metrics Abstract We examined evoked and induced modulations in theta, alpha and gamma oscillations, and also the P2 and late positive component of event-related potentials, during a visual discrimination task with target and nontarget letters. Results for target letters showed a decrease in the amplitude of alpha-band (10–11 Hz) activity and an increase in theta (4–7 Hz) and gamma (40–44 Hz) activities around 350 ms after stimulation. P2 and late positive component presented a higher amplitude to target than to repeated nontarget letters. Alpha reduction was inversely related to theta and late positive component increase. Moreover, gamma oscillation amplitude was directly related to theta amplitude. The findings suggest the importance of occipitoparietal alpha reduction for the development of task-related neuronal activity. © 2007 Lippincott Williams & Wilkins, Inc.