Increased attention towards threatening stimuli in both the external and internal
environments is thought to be a factor in the causation and maintenance of pathological
anxiety. Attentional biases for threatening information have been demonstrated in anxiety
disorders, however the cortical mechanisms involved remain unclear. In this investigation,
an Emotional Stroop task consisting of neutral, positive, depression-related and anxietyrelated
words, was used to investigate attentional biases in 14 Panic Disorder patients and
32 psychiatrically healthy controls. The standard colour-word Stroop was also performed
to determine whether any general cognitive deficits exist in Panic Disorder. Steady-state
probe topography (SSPT), a brain electrical activity imaging methodology, was used to
investigate participants' brain activity during performance of the tasks. It was hypothesised
that Panic Disorder is associated with specific biases for disorder-specific information and
thus patients would exhibit increased interference for anxiety-related words only, compared
to neutral words. Mean reaction times for the Standard Stroop was similar for the two
groups. For the Emotional Stroop task, neither group showed an interference effect for any
emotional category. However, Panic Disorder patients performed the Emotional Stroop
significantly more slowly than the Controls. The SSPT data suggest that the Standard and
Emotional Stroop tasks are associated with different patterns of brain activity in the Control
and Panic Disorder groups despite the similarities in the reaction time data. Specifically,
the Standard Stroop was marked by strong temporo-parietal excitation in the Panic Disorder
group only. In addition, anterior SSVEP patterns further differentiated between the Control
and Panic Disorder groups. The most striking finding for the Emotional Stroop was strong
sustained bilateral temporo-parieto-occipital excitation in the Panic Disorder group. In
addition, a subgroup of the Controls exhibited increased interference for anxiety-related
words and therefore the brain activity for this group and the remainder of Controls who did
not show interference was analysed separately. It was found that the presence of
interference for anxiety-related words was associated with right prefrontal inhibition prior
to response. Other time-varying changes in the SSVEP further distinguished between the
subgroup of Controls who showed an interference effect and those who did not.
| Identifer | oai:union.ndltd.org:ADTP/216587 |
| Date | January 2006 |
| Creators | Athan, Donna Michelle, n/a. |
| Publisher | Swinburne University of Technology. |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://www.swin.edu.au/), Copyright Donna Michelle Athan |
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