Prestimulus oscillatory phase at 7 Hz gates cortical information flow and visual perception

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• The perception of visual information is often assumed to be continuous.
• Recent research suggests visual sampling occurs rhythmically, within the 5-10 Hz frequency range.
• Brain oscillations, particularly electroencephalography (EEG) signals, are hypothesized to underlie this perceptual rhythmicity.

Purpose of the Study:

• To investigate whether ongoing brain oscillations play a causal role in the rhythmic nature of visual perception.
• To determine if pre-stimulus oscillatory phase predicts perceptual performance and inter-regional brain communication.
• To explore the functional connectivity between visual processing areas during a perceptual task.

Main Methods:

• Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) were recorded.
• Participants performed a contour integration task.
• Analysis included psychophysiological interaction (PPI) and dynamic causal modeling (DCM) to assess functional connectivity.

Main Results:

• The phase of ongoing 7 Hz brain oscillations prior to stimulus onset predicted perceptual performance.
• Pre-stimulus oscillatory phase was linked to functional connectivity between the left lateral occipital cortex and right intraparietal sulcus.
• This connectivity reflected bidirectional information flow, supporting the role of oscillations in inter-regional communication.

Conclusions:

• Human brain oscillations, specifically at ~7 Hz, periodically gate visual perception.
• These oscillations provide transient time windows for long-distance cortical information transfer.
• This mechanism may explain the rhythmic nature of human visual perception.