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Controlling attention to emotional stimuli: a combined functional neuroimaging and functional genomics approach

Final Activity Report Summary - EMOTION (Controlling attention to emotional stimuli: a combined functional neuroimaging and functional genomics approach)

Problems in controlling attention to emotional stimuli have long been recognised to play a central role in anxiety. However, the relative role of brain mechanisms involved in controlling attention, in particular the lateral prefrontal cortex, versus that of brain mechanisms involved in detecting the presence of negative or 'threat-related' emotional stimuli, in particular the amygdale, has been fairly poorly understood. The undertaken research attempted to examine these issues.

In particular, the following questions were addressed:
- Are prefrontal cortical brain mechanisms recruited when we try to control our attention and ignore emotional but task-irrelevant stimuli?
- Is this only the case when 'distractor' stimuli are negative and signal potential threat or is this also the case when they are positive and signal potential reward?
- Do anxious individuals show poorer recruitment of these mechanisms?
- Can we identify common genetic variations which influence the activation of these brain regions?
- In addition, is the amygdala specifically responsive to the presence of threat-related stimuli?
- Is this response greater in anxious individuals?
- Is it influenced by how attentionally demanding the task to be performed is made?
- Are there genetic variants which influence activity in this brain region in response to threat-related stimuli?

The research supported by this fellowship produced a number of important results. Firstly, it appeared that when the task engaged in was highly attentionally demanding, even anxious people did not show an amygdala response to negative stimuli that signalled potential threat. This had a number of important implications. It suggested that being overly involved in a given task might lead us to miss genuine signals of danger. Secondly, aiding anxious individuals to engage in tasks more effectively might be one way to help them to prevent their attention being captured by threat cues which low anxious individuals were able to ignore.

Through combining genotyping with functional Magnetic resonance imaging (MRI), I was also able to investigate the impact of specific genes upon brain activity linked to attentional capture by emotional stimuli. This helped us to identity specific genetic variants or 'polymorphisms' that influenced the neural mechanisms of relevance. More specifically, this research showed that a polymorphism in the Catechol-o-methyltransferase (COMT) gene influenced activity in the prefrontal mechanisms that helped us to control our attention to emotional stimuli as well as to perform demanding cognitive tasks. In addition, it produced promising initial findings suggesting that a polymorphism in the serotonin transporter (5HTT) gene influenced how strongly the amygdala responded to threat-related distractors.

Hopefully in future work, we could examine how these genetic variants interact to jointly influence recruitment of the brain regions that help us control our attention to emotional stimuli. The hope was that through this we might begin to build up a model of the genes that lead some people to be more vulnerable to anxiety than others.