State-dependent perception and perceptual reversals during intermittent binocular rivalry: An electrical neuroimaging study.

The object-context relationship and valence are two important stimulus attributes that affect visual perception. Although previous studies reveal how these two factors affect visual perception individually, the interplay between valence with congruent or incongruent object-context associations during visual perception is explored scarcely. Further, what is perceived, is affected by the intrinsic state of the brain at the moment of appearance of the stimulus which could be assessed by EEG microstates. Hence, the current study was designed to explore how the pre-stimulus EEG microstate influences the perception of emotional congruent and incongruent stimuli as well as perceptual reversals and stability during an intermittent binocular rivalry. Results revealed the association of specific pre-stimulus microstates with the perception of neutral and negative congruent stimuli as well as perceptual reversals and stability. Electrical neuroimaging of these microstates showed higher activation in the precuneus and middle occipital gyrus preceding the perception of neutral congruent stimuli and lingual gyrus preceding the perception of negative congruent stimuli. Increased source activity in superior temporal gyrus and superior frontal gyrus was found preceding stability and lower activation in parahippocampal gyrus was observed preceding reversals. Together these results suggest that the pre-stimulus activation of areas involved in visual priming, retrieval, and semantics leads to congruent perception. Pre-stimulus DMN suppression was required for perceptual reversals whereas stability was accompanied by pre-stimulus activation of areas related to the specific nature of the stimulus. Therefore, we propose that in addition to stimulus attributes, the pre-stimulus intrinsic brain activity could be an important determinant of the performance.