Cognitive control over emotional action tendencies is an important component of successful social interactions. It employs a possibility to suppress automatic action tendencies and produce responses that are more deliberate. Control over tendencies to approach or avoid gives a person a wider array of possible actions and therefore better behavioural flexibility. In the case of social anxiety disorder, irregular use of such control might lead to symptomatic avoidance of aversive stimuli and can be detrimental to the quality of life of the affected individual. It is therefore important to understand the underlying neural mechanisms of emotional cognitive control.
Studies of cognitive control mechanisms often demonstrate an important contribution of prefrontal regions to cognitive control implementation. More specifically, the anterior prefrontal cortex (aPFC) is thought to orchestrate selection of response strategies by inhibiting areas of automatic processing such as amygdala and fusiform face area (FFA). Most of the studies focus on this top-down role of the aPFC. However, one question that remains is how cognitive control might be reflected in the early phase of processing, when the need for control is known in advance.
Alpha gating is a mechanism that was shown to play a role in supressing inessential cortical pathways in brain processing for mostly perceptual and attentional tasks. This thesis addresses whether such alpha power modulation also occur during the implementation of cognitive control over emotional biases. A version of an approach-avoidance task (AAT) was used in combination with magnetoencephalography (MEG) and magnetic resonance imaging (MRI) to check for evidence of sensory information gating by alpha activity when subjects are asked to supress their emotional action tendencies. In this task, subjects responded to emotional faces by approaching or avoiding motion. In the congruent condition, movements were in accordance with emotional face valance and in the incongruent, they were in opposition. Hypothesis stated that there would be higher alpha band power in the incongruent compared to the congruent task condition over visual areas. Alpha power differences were estimated at the channel and source level for the whole brain using non-parametric permutation statistics and cluster correction for multiple comparison.
There was a significance difference between the more control-demanding incongruent condition and the more automatic congruent condition on the source level. There was no difference on the sensory level. The results suggest that alpha gating might be involved in early sensory processing during control over emotional action tendencies. Specifically, activity in the FFA might be an interesting target of further exploration.
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