Dimensions of spider phobia and proposed neural circuitry

Specific phobias have traditonally been viewed as a unitary construct. There is emerging evidence however that certain cognitive vulnerabilities exist pertaining to generic stimulus features (i.e., movement, size) proposed to underlie anxiety. Treatment studies further show that feature-specific exposure to feared stimuli exhibit clinically significant and robust outcomes in phobic populations. Taken together these findings suggest that phobic fear may not be limited to a specified object per se, but rather inherent stimulus properties that, once elucidated, may be used to effectively treat phobic disorders via idiosyncratic exposure therapy. While neuroimaging studies have revealed post-treatment changes in rCBF for anxiety disorders, there is no evidence to date that has investigated how salient phobogenic stimulus features are processed by the brain. The present neuroimaging treatment study aims to identify differential patterns of neurological activity associated with phobic dimensions, and how this neurological profile is mediated by looming reduction techniques incorporated into evidence-based psychological therapy. Within-subjects neuroimaging treatment study using magnetoencephalography (MEG) in a dot-probe experimental paradigm. Preliminary survey results have revealed that highly spider-phobic individuals perceive the salience of phobic dimensions nonuniformly, with size and movement best predicting overall spider fear. In addition, the Spider Dimensions Survey appears to be a valid and reliable measure to assess pre-cognitive threat-related attentional capture of spiderphobic dimensions. Initial findings demonstrate the differential salience of phobic dimensions among highly phobic individuals compared to normal controls. Subsequent imaging data will seek to provide a spatio-temporal neuranatomical profile of phobogenic stimulus features, and their mitigation by specialised exposure therapy