Task-related modulation of anterior theta and posterior alpha EEG reflects top-down preparation
1 Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, USA
2 Brain Korea 21 Project for Medical Science, Department of Radiology, Nuclear Medicine and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea
BMC Neuroscience 2010, 11:79 doi:10.1186/1471-2202-11-79Published: 28 June 2010
Prestimulus EEG alpha activity in humans has been considered to reflect ongoing top-down preparation for the performance of subsequent tasks. Since theta oscillations may be related to poststimulus top-down processing, we investigated whether prestimulus EEG theta activity also reflects top-down cognitive preparation for a stimulus.
We recorded EEG data from 15 healthy controls performing a color and shape discrimination task, and used the wavelet transformation to investigate the time course and power of oscillatory activity in the signals. We observed a relationship between both anterior theta and posterior alpha power in the prestimulus period and the type of subsequent task.
Since task-differences were reflected in both theta and alpha activities prior to stimulus onset, both prestimulus theta (particularly around the anterior region) and prestimulus alpha (particularly around the posterior region) activities may reflect prestimulus top-down preparation for the performance of subsequent tasks.