Visibility reflects dynamic changes of effective connectivity between V1 and fusiform cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• Understanding the neural basis of conscious visual perception is crucial.
• Early visual cortex activity was traditionally thought to underpin basic feature visibility, like brightness.

Purpose of the Study:

• To investigate the neural correlates of visual stimulus visibility beyond early visual processing.
• To examine the role of brain activity and connectivity in conscious perception under masking conditions.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Metacontrast masking was employed to manipulate stimulus visibility.
• Analysis focused on correlations between brain activity, psychometric visibility, and effective connectivity.

Main Results:

• fMRI activity in early visual cortex did not correlate with parametric changes in brightness stimulus visibility.
• Visibility correlated with activity in higher visual regions, parieto-frontal areas, and surprisingly, the unstimulated stimulus surround in primary visual cortex.
• Decreased visibility was linked to a specific decoupling between early visual cortex and higher visual areas.

Conclusions:

• Conscious visual perception of brightness is not solely represented in early visual cortex.
• Later visual and parieto-frontal regions play a significant role in determining visual awareness.
• Dynamic changes in effective connectivity between brain regions are closely associated with visual perception.