Early top-down influences on bistable perception revealed by event-related potentials

Area of Science:

• Cognitive Neuroscience
• Visual Perception
• Psychophysics

Background:

• Bistable perception involves alternating between two interpretations of ambiguous stimuli.
• The debate continues regarding whether bottom-up sensory input or top-down cognitive control drives perceptual alternations.
• Event-related potentials (ERPs), specifically the reversal negativity (RN), offer a temporal measure of perceptual reversals.

Purpose of the Study:

• To investigate the influence of top-down control on bistable perception.
• To determine if manipulating observers' intentions affects early electrophysiological markers of perceptual reversals.
• To contribute to resolving the bottom-up vs. top-down debate in bistable perception.

Main Methods:

• Measured event-related potentials (ERPs) during bistable perception.
• Manipulated observers' intentional approach: intention-to-reverse, intention-to-stabilize, or passive observation.
• Analyzed the reversal negativity (RN) component, an ERP marker of perceptual change.

Main Results:

• The reversal negativity (RN) showed enhanced amplitude when observers intended to reverse perception compared to a passive approach.
• This enhancement suggests an early (around 150 ms) top-down influence on the perceptual reversal process.
• No significant differences were observed for the intention-to-stabilize condition.

Conclusions:

• Top-down control, specifically the intention to reverse, exerts an early influence on bistable perception.
• Findings support theories involving attentional mechanisms in driving perceptual alternations.
• The study provides electrophysiological evidence for the role of voluntary attention in modulating early visual processing during bistable perception.