Neural basis of cognitive-emotional processing in neuroticism

The personality trait neuroticism is a predictor for psychopathology (Ormel et
al., 2004). The personality trait neuroticism has been correlated to specific
brain regions. Subjects brain activation to viewing negative, relative to
positive pictures correlated significantly with participants' neuroticism
scores in left frontal and temporal cortical regions in a study by Canli et al.
(2001). Other cognitive (Deckersbach et al., 2006; Eisenberger et al., 2005;
Paulus et al., 2003) and emotional (Hariri et al., 2002) tasks have been used
to identify brain areas correlated with the subjects* neuroticism scores of the
NEO Five-Factor Inventory. In all the above studies, predictions could be made
about the subject*s personality by the reactivity of the brain during the
experiments.
However, there has previously been no research that tested the different
aspects of neuroticism and relate it to different neural circuits.

The objective of this study is to test the hypothesis that the aspect of
neuroticism "irritability" is associated with overactivation of specific brain
areas during frustration while the aspect "anxious-depressed" is associated
with overactivation during critique and judgment in a social context.

We will test different facets of neuroticism by using different tasks. There
will be three tasks and five conditions in the fMRI experiment. The following
psychological facets typical for personality trait neuroticism will be tested:
anxiety and social judgement proneness, self-conscientiousness, emotional
decision-making, and irritability, all reflecting different facets of
neuroticism we are interested in. The three overt tasks include: facial
expression task for anxiety proneness, the Ultimatum Game for emotional
decision-making and the altered N-Back task for irritability. The five
conditions reflect the different states we will try to put the subjects in.
We will use subjects scoring high on the subscales *irritability* on the one
hand, and those that score high on the subscale *anxiety* and *fear for
negative self evaluation* on the other. These groups will perform 3
cognitive-emotional tasks as well as get minor external stressors during our
fMRI experiment. The two groups of subjects will be compared with a control
group.

Subjects will be exposed to a magnetic field of 3 Tesla and rapidly alternating
magnet gradients and radio frequency fields. This field strength is used on a
routinely basis in fMRI and MRI research. So far, no side effects have been
described. On rare occasions, a peripheral nerve (abdomen) is stimulated by the
changing magnet gradients. This will cause an itching feeling, but it is not
harmful.