Investigating phobic specificity with standardized low resolution brain electromagnetic tomography (sLORETA).
The current study investigated differential sources of late event-related potentials (ERPs) in two subtypes of specific phobia using sLORETA (standardized low resolution brain electromagnetic tomography). In two experiments, 14 spider-phobic patients (and controls), and 14 dentophobic patients (and controls) were confronted with disorder-relevant and affectively neutral pictures while an electroencephalogram was recorded. Mean ERP amplitudes were extracted in the time windows of 300-450ms (P300) and 450-800ms (late positive potential, LPP). Analyses revealed that both spider phobics and dental phobics showed enhanced current density in parietal regions (i.e., cuneus, precuneus) for the P300 time frame when exposed to disorder-specific contents. This result can be interpreted to reflect automatic attention allocation. Spider phobics additionally displayed greater current density in the insula and the anterior/posterior cingulate cortex in the LPP time window relative to controls. Most likely, the phylogentically based spider phobia is characterized by a deeper and more prolonged attention engagement than dental phobia. Our findings are in good accordance with existing brain imaging studies and underline that source localization is a useful alternative for identifying relevant cortical regions in subtypes of specific phobia.
University of Graz, Institute of Psychology, Department of Clinical Psychology, Universitätsplatz 2/III, A-8010 Graz, Austria. wilfried.scharmueller@uni-graz.at
Wilfried
W
Scharmüller
Verena
V
Leutgeb
Axel
A
Schäfer
Anne
A
Schienle
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D010698:Phobic Disorders / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D011569:Psychiatric Status Rating Scales; D014057:Tomography, X-Ray Computed; D055815:Young Adult