A research group led by Prof. ZHANG Peng from the Institute of Biophysics of the Chinese Academy of Sciences has revealed how the human brain resolves perceptual conflicts and generates conscious perception through local inhibition in the sensory cortex and feedback integration from the parietal cortex.

Using ultra-high-resolution 7-tesla functional magnetic resonance imaging (7T fMRI), the researchers performed mesoscale functional imaging of cortical columns, cortical layers, and subcortical nuclei.

Their findings were published in Nature Human Behaviour on November 13.

The researchers employed a binocular rivalry paradigm to examine how competing visual inputs are processed. They found that binocular rivalry stems from lateral inhibition in the superficial layers of ocular dominance columns (ODCs) in the primary visual cortex (V1), rather than in the lateral geniculate nucleus (LGN) of the thalamus.

This 7T fMRI evidence resolves long-standing discrepancies between electrophysiological findings in awake monkeys and traditional 3T fMRI studies, demonstrating that the resolution of visual conflict is driven by inhibitory microcircuits in the early sensory cortex, not by thalamic mechanisms.

The study also shows that, although the participants were unaware of which eye received the visual stimulus, eye-specific feedback signals from the intraparietal sulcus (IPS) could modulate and synchronize local competitions in both the superficial and deep layers of V1, integrating them into coherent conscious perception.

Together, these findings uncover the mesoscale neural mechanisms by which the human brain resolves perceptual conflicts to generate conscious awareness.

This work provides important functional evidence at the mesoscale level for the neural basis of human perceptual consciousness.

The Phenomenon of Binocular Rivalry (Image by ZHANG Peng's group)

Mesoscale Neural Mechanisms of Binocular Rivalry in Humans (Image by ZHANG Peng's group)

A Multilevel Model of Binocular Rivalry (Image by ZHANG Peng's group)