Theta-gamma coupling during perceptual closure in human EEG
Neuronal oscillations; cross frequency coupling; theta–gamma phase-amplitude coupling; working memory.
Phase-amplitude coupling (PAC) between neuronal oscillations in the theta (3-6Hz) and gamma (30-90Hz) frequency bands is potentially the basis of sensory integration, memory, and attentional selection mechanism. In the present work, we present evidence that PAC between theta and gamma in the prefrontal (PFC) and posterior parietal (PPC) cortices, respectively, is responsible for perceptual closure in a face recognition test using electroencephalography (EEG). The role played by executive functions in this task was also verified through correlation measures with the performance in general intelligence (IQ) and working memory tests. The theta-gamma PAC was quantified with a modulation index (MI). The results show that perceptual closure is associated with an increase in the MI. However, we did not find significant correlations between the variables. Thus, our study brings more evidence that PAC underlies the long-range communication between cortical areas and highlights the putative role of working memory in supporting visual Gestalt formulation in the parietal cortex.