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Attentional biases for threat in anxiety an fmri study

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Attentional biases for threat in anxiety an fmri study Powered By Docstoc
					 Neural systems for
 attention to threat in
anxiety: an fMRI study
 Leor Shoker, Nazanin Derakshan,
   Anne Richards & Elaine Fox
                                 Background
   Anxiety is associated with enhanced attention to threat and poor top-
    down regulation of threat (Bishop, 2007; Eysenck, Derakshan, et al.
    2007; Fox, Derakshan, & Shoker, under review)
   Dorsal fronto-parietal networks contribute to top-down
    selection of stimuli
        Intraparietal sulcus (IPS) & frontal eye fields
          • Involved in orienting visiospatial attention (Corbetta & Shulman 2002, Ettinger et al. 2007, Ford et
             al. 2005)


   Orbito-frontal cortex (OFC) and ventrolateral prefrontal
    cortex promote shifts in processing resources in attentional
    conflict situations (Pourtois et al. 2006). IPS                               Orbito-frontal
                                                                                  cortex




   Question: Whether OFC and ventral networks react
    differently towards threat and if this is modulated by anxiety?
                   Attention Task
• Pre-test for anxiety (high vs. low)
• Visual field of emotional face (left vs. right)
• Valence of face (fearful vs. happy)
• Validity of target (valid vs. invalid)



                                cue
                                                              Predictions

                                               More activity in the OFC for targets
                                               invalidly cued by fearful faces compared
                    100-300ms         target   to validly cued targets. This effect will be
                                               greater in HA compared with LA.

                                               More activity in IPS for valid targets
                                               preceded by fearful faces. This effect will
                                               be greater in HA compared with LA.
                       Proposed Study
Participants
     • 32, right-handed, 16 high and 16 low-anxious (pre-screened)


Task Details
     • 300 trials in total (160 cue + target (50% match), 80 cue only, 60 null trials (just
     fixation)),
         • 20 trials per condition
     • duration ~= 45 mins


Scanning details
     • Whole brain fMRI
         (TR=2400ms, TE=40ms, 3x3x3mm resolution)

     • 32 slices

     • ISI: 4-6 seconds
     • Event related design

				
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posted:4/24/2013
language:English
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