Shifts in gamma phase–amplitude coupling frequency from theta to alpha over posterior cortex during visual tasks

• Published in: Frontiers in human neuroscience Vol. 4; p. 191
• Main Author: Voytek, Bradley
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 2010; Frontiers Media S.A
• Subjects: alpha; Cross-frequency coupling; electrocorticogram; Electrodes; Electroencephalography; gamma; Medicine; Memory; Neural networks; Neuroscience; Oscillations; theta; Theta rhythms; Trends; Visual cortex; United States > US; California; electrocorticogram; alpha; cross-frequency coupling; phase–amplitude coupling; oscillations; theta; gamma
• ISSN: 1662-5161; 1662-5161
• DOI: 10.3389/fnhum.2010.00191

The phase of ongoing theta (4-8 Hz) and alpha (8-12 Hz) electrophysiological oscillations is coupled to high gamma (80-150 Hz) amplitude, which suggests that low-frequency oscillations modulate local cortical activity. While this phase-amplitude coupling (PAC) has been demonstrated in a variety of tasks and cortical regions, it has not been shown whether task demands differentially affect the regional distribution of the preferred low-frequency coupling to high gamma. To address this issue we investigated multiple-rhythm theta/alpha to high gamma PAC in two subjects with implanted subdural electrocorticographic grids. We show that high gamma amplitude couples to the theta and alpha troughs and demonstrate that, during visual tasks, alpha/high gamma coupling preferentially increases in visual cortical regions. These results suggest that low-frequency phase to high-frequency amplitude coupling is modulated by behavioral task and may reflect a mechanism for selection between communicating neuronal networks.