Interhemispheric connections shape subjective experience of bistable motion

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Visual Perception

Background:

• The corpus callosum connects the brain's hemispheres, crucial for integrating visual information from different visual fields.
• While split-brain studies reveal callosal functions, their role in conscious visual perception in healthy individuals remains less understood.
• Investigating interhemispheric integration is key to understanding conscious visual processing.

Purpose of the Study:

• To identify specific callosal connections that contribute to conscious visual perception of motion.
• To explore the role of interhemispheric integration in subjective visual experiences.
• To link microstructural properties of callosal fibers to perceptual outcomes.

Main Methods:

• Employed diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) in healthy human participants.
• Utilized the 'motion quartet' stimulus, an ambiguous apparent motion display, to probe visual perception.
• Tracked individual callosal segments connecting motion-sensitive visual areas.

Main Results:

• Microstructural integrity of callosal segments linking the human MT/V5 complex (hMT/V5+) predicted observers' conscious perception of motion.
• This predictive relationship was specific to connections between hMT/V5+ regions.
• Connections involving the primary visual cortex (V1) or other callosal areas did not show a similar link to perception.

Conclusions:

• Specific callosal connections, particularly those involving hMT/V5+, are critical for conscious visual motion perception.
• The microstructure of these interhemispheric pathways directly influences subjective visual experience.
• This highlights the importance of interhemispheric communication for complex visual processing.