Consciousness and emotion

03/06/2011 by admin.

Is conscious experience affected by what we feel? That is the question that Romer and others posed themselves (citation). They also looked at the role played by the anterior cingulate cortex in the consciousness of emotion. This part of the cortex is deep within the middle of the brain, wrapped around the corpus callosum, the main connection between the two hemispheres. The top of this wrap is thought to be concerned with cognition, reward and consciousness. The bottom of the wrap is thought to be concerned with emotion and motivation. This could be the obvious center for emotion and consciousness to interact.

Here is the abstract:

Emotion and reward have been proposed to be closely linked to conscious experience, but empirical data are lacking. The anterior cingulate cortex (ACC) plays a central role in the hedonic dimension of conscious experience; thus potentially a key region in interactions between emotion and consciousness. Here we tested the impact of emotion on conscious experience, and directly investigated the role of the ACC. We used a masked paradigm that measures conscious reportability in terms of subjective confidence and objective accuracy in identifying the briefly presented stimulus in a forced-choice test. By manipulating the emotional valence (positive, neutral, negative) and the presentation time (16 ms, 32 ms, 80 ms) we measured the impact of these variables on conscious and subliminal (i.e. below threshold) processing. First, we tested normal participants using face and word stimuli. Results showed that participants were more confident and accurate when consciously seeing happy versus sad/neutral faces and words. When stimuli were presented subliminally, we found no effect of emotion. To investigate the neural basis of this impact of emotion, we recorded local field potentials (LFPs) directly in the ACC in a chronic pain patient. Behavioural findings were replicated: the patient was more confident and accurate when (consciously) seeing happy versus sad faces, while no effect was seen in subliminal trials. Mirroring behavioural findings, we found significant differences in the LFPs after around 500 ms (lasting 30 ms) in conscious trials between happy and sad faces, while no effect was found in subliminal trials. We thus demonstrate a striking impact of emotion on conscious experience, with positive emotional stimuli enhancing conscious reportability. In line with previous studies, the data indicate a key role of the ACC, but goes beyond earlier work by providing the first direct evidence of interaction between emotion and conscious experience in the human ACC.

It would seem unlikely that the anterior cingulate cortex would be the only place where emotion has an affect on consciousness. More importantly, we do not really see what the interaction is – what is affecting what has to be a guess. Still it is very interesting that this particular emotional effect only occurs if the experience rises to consciousness. So the emotion probably has no effect on the mechanism for rising or not rising to consciousness. However once the experience does rise to consciousness, then the strength of its appearance seems to be affected by the emotional component. On the other hand, previous work indicates that subliminal emotional priming does appear to have some limited effect on behaviour and mood, even though we are not aware of it. So, as usual it’s still complicated.

Romer Thomsen K, Lou HC, Joensson M, Hyam JA, Holland P, et al (2011). Impact of Emotion on Consciousness: Positive Stimuli Enhance Conscious Reportability PLoS ONE DOI: 10.1371/journal.pone.0018686

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