Multiple Mechanisms of Consciousness: The Neural Correlates of Emotional Awareness

Abstract

Emotional stimuli, including facial expressions, are thought to gain rapid and privileged access to processing resources in the brain. Despite this access, we are conscious of only a fraction of the myriad of emotion-related cues we face everyday. It remains unclear, therefore, what the relationship is between activity in neural regions associated with emotional representation and the phenomenological experience of emotional awareness. We used functional magnetic resonance imaging and binocular rivalry to delineate the neural correlates of awareness of conflicting emotional expressions in humans. Behaviorally, fearful faces were significantly more likely to be perceived than disgusted or neutral faces. Functionally,increasedactivitywasobservedinregionsassociatedwithfacialexpressionprocessing,includingtheamygdalaandfusiformgyrus during emotional awareness. In contrast, awareness of neutral faces and suppression of fearful faces were associated with increased activity in dorsolateral prefrontal and inferior parietal cortices. The amygdala showed increased functional connectivity with ventral visual system regions during fear awareness and increased connectivity with perigenual prefrontal cortex (pgPFC; Brodmann's area 32/10) when fear was suppressed. Despite being prioritized for awareness, emotional items were associated with reduced activity in areas considered critical for consciousness. Contributions to consciousness from bottom-up and top-down neural regions may be additive, such that increased activity in specialized regions within the extended ventral visual system may reduce demands on a frontoparietal system important for awareness. The possibility is raised that interactions between pgPFC and the amygdala, previously implicated in extinction, may also influence whether or not an emotional stimulus is accessible to consciousness.

Accelerated HF-rTMS in treatment-resistant unipolar depression: Insights from subgenual anterior cingulate functional connectivity

“…Ventral-rostral portions of the ACC and parts of the vmPFC have a regulatory role with respect to limbic regions involved in generating emotional responses (Etkin et al 2011). The pgPFC is implicated in mechanisms of consciousness and emotional awareness (Amting et al 2010). Given the role of the pgPFC in emotion-regulative processes (Ochsner and Gross 2005) the observed enhanced functional connectivity between sgACC and pgPFC could be essential for the suppression of depressive symptoms.…”

Functional neural correlates of emotional expression processing deficits in behavioural variant frontotemporal dementia

“…Functional imaging studies in humans have demonstrated that ventral visual cortices, specifically the lateral fusiform areas, show more activation for emotional (angry, happy, fearful, sad or disgusted) versus neutral faces, [13][14][15]30 and for higher versus lower emotional intensities. 39 Research suggests that projections from limbic regions modulate activity in the ventral visual stream, augmenting activation in the fusiform cortex for emotionally salient stimuli.…”

“…It has been demonstrated that emotionrelated subcortical activity serves to boost stimulus representation in the ventral visual system in a bottom-up manner. 13,30,31 Face perception tasks limiting ventral visual (bottom-up) input have detected increased activity in regions such as the infer ior parietal lobule, posterior cingulate cortex, dorsolateral prefrontal cortex and precuneus. 30,48 Following this model, in both patients with bvFTD and controls, high-intensity expressions would be expected to generate a greater limbic response than low-intensity expressions, leading to a reduced need for attentional compensation during the viewing of high-intensity faces.…”

“…Recent evidence implicates parietal regions in stabilizing goal-relevant stimuli that are weakly represented, perhaps owing to reduced afferent input from emotion-related brain regions. 30,31 Accordingly, we hypothesized that increased activity in this network may reflect increased top-down efforts to compensate for reduced limbic input to the ventral visual stream in patients with bvFTD. We predicted that compared with controls, patients with bvFTD would show augmented posterior parietal and posterior cingulate cortex activation during low-compared with highintensity emotional faces (i.e., when task demands are greatest).…”

Neuroanatomical Correlates of Perceived Usability

“…We found activation in the fusiform gyrus, which is involved in emotional facial expression, and in the middle frontal gyrus (BA9), which shows activity during emotional suppression [4]. Another evidence is the activation seen in the superior frontal gyrus (BA10) and the anterior cingulate gyrus in the contrast of Usability vs. baseline.…”