Attention Modulates the Neural Oscillation of Theta Frequency in Audiovisual Integration

Abstract

The ability to integrate information reaching us is a fundamental requirement for forming a coherent mental representation of our environment. One mechanism that has been proposed to underlie multisensory information across distributed cortical networks is transient synchronization of neural oscillations. Multisensory integration is a complex information processing, which is modulated by attention. In this study, we intended to explore the modulation of attention on neural oscillation of theta frequency band in audiovisual integration, by manipulating active attention to both visual and auditory stimuli or not attended at all. We analyzed the power of theta band, degree and long-range connectivity strength of functional brain networks in theta band. Our results showed that there was a significant difference in the power of theta frequency band between attended and unattended audiovisual integration, and the output degree of prefrontal area in attended theta network is significant higher than that in unattended network. Moreover, the strength of long-range connectivity from frontal area to parieto-occipital area is also significant higher in attended theta network of audiovisual integration, comparing to that in unattended theta network. We speculated that the top-down attention modulates the audiovisual integration, by increasing the neural oscillation of theta band, and that the top-down attention transmits theta signals to other regions through the frontal region, guiding other regions to integrate the visual and auditory inputs consciously.