Dissociating the Neural Correlates of Consciousness and Task Relevance in Face Perception Using Simultaneous EEG-fMRI

Abstract

Current theories of visual consciousness disagree about whether it emerges during early stages of processing in sensory brain regions or later when a widespread frontoparietal network becomes involved. Moreover, disentangling conscious perception from task-related postperceptual processes (e.g., report) and integrating results across different neuroscientific methods remain ongoing challenges. The present study addressed these problems using simultaneous EEG-fMRI and a specific inattentional blindness paradigm with three physically identical phases in female and male human participants. In phase 1, participants performed a distractor task during which line drawings of faces and control stimuli were presented centrally. While some participants spontaneously noticed the faces in phase 1, others remained inattentionally blind. In phase 2, all participants were made aware of the task-irrelevant faces but continued the distractor task. In phase 3, the faces became taskrelevant. Bayesian analysis of brain responses demonstrated that conscious face perception was most strongly associated with activation in fusiform gyrus (fMRI) as well as the N170 and visual awareness negativity (EEG). Smaller awareness effects were revealed in the occipital and prefrontal cortex (fMRI). Task-relevant face processing, on the other hand, led to strong, extensive activation of occipitotemporal, frontoparietal, and attentional networks (fMRI). In EEG, it enhanced early negativities and elicited a pronounced P3b component. Overall, we provide evidence that conscious visual perception is linked with early processing in stimulus-specific sensory brain areas but may additionally involve prefrontal cortex. In contrast, the strong activation of widespread brain networks and the P3b are more likely associated with task-related processes.

The Effects of Spatial Attention Focus and Visual Awareness on the Processing of Fearful Faces: An ERP Study

“…The VAN has been suggested to index the ERP differences between supraliminal and subliminal conditions [43]. Here, we show that complex and meaningful stimuli like human faces are associated with a large VAN when they are clearly visible to the participants and gain access to awareness, compared to when they are rendered subliminal and hence not consciously processed, consistent with previous studies also using face stimuli [22,44,45].…”

Decoding perceptual awareness across the brain with a no-report fMRI masking paradigm

“…In addition to being important for future research, consideration of multivariate methods is also critical in assessing previous no-report studies. Although a wide variety of prior results have shown the importance of no-report paradigms for consciousness studies, virtually all of them fail to use more nuanced decoding measures like the ones described here, 24,[26][27][28][29][30]32,34,62 but see Kapoor et al 35 and Dwarakanath et al 62 In fact, in a prior study from our laboratories, we found that one particular candidate signature of conscious processing, the P3b, completely disappeared in a no-report paradigm like the one described here, which goes against key predictions made by the global neuronal workspace theory. 30 This previous result is perfectly consistent with our univariate measures, which found that overall activity levels in the frontal lobe completely disappeared in the no-report conditions (Figures 3 and 4).…”

A connectome-based model of conscious access in monkey cortex

“…We do not explicitly try to model this very slow cortical dynamic activity here. Our model is agnostic as to whether the entire late distributed activity pattern represents conscious access alone, or whether some of the activity could prepare a conscious report, or other post-access conscious processing (Cohen et al 2020;Dellert et al 2021;Pitts et al 2018Pitts et al , 2012Pitts et al , 2014Schlossmacher et al 2020;Sergent et al 2021). Simulation of activity patterns during cognitive tasks in connectome-based dynamical models is in its infancy, and the types of tasks that have been simulated are particularly simple (Froudist-Walsh et al 2021a;Mejias and Wang 2022).…”