Symptom provocation and reduction in patients suffering from spider phobia

Clinical Psychology, Karl-Franzens-Universität Graz, Universitätsplatz 2/III, 8010 Graz, Austria.
European Archives of Psychiatry and Clinical Neuroscience (Impact Factor: 3.36). 12/2007; 257(8):486-493. DOI: 10.1007/s00406-007-0754-y
Source: PubMed

ABSTRACT Neurofunctional mechanisms underlying cognitive behavior therapy (CBT) are still not clearly understood. This functional magnetic
resonance imaging (fMRI) study focused on changes in brain activation as a result of one-session CBT in patients suffering
from spider phobia. Twenty-six female spider phobics and 25 non-phobic subjects were presented with spider pictures, generally
disgust-inducing, generally fear-inducing and affectively neutral scenes in an initial fMRI session. Afterwards, the patients
were randomly assigned to either a therapy group (TG) or a waiting list group (WG). The scans were repeated one week after
the treatment or after a one-week waiting period. Relative to the non-phobic participants, the patients displayed increased
activation in the amygdala and the fusiform gyrus as well as decreased activation in the medial orbitofrontal cortex (OFC)
during the first exposure. The therapy effect consisted of increased medial OFC activity in the TG relative to the WG. Further,
therapy-related reductions in experienced somatic anxiety symptoms were positively correlated with activation decreases in
the amygdala and the insula. We conclude that successful treatment of spider phobia is primarily accompanied by functional
changes of the medial OFC. This brain region is crucial for the self-regulation of emotions and the relearning of stimulus-reinforcement

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    ABSTRACT: To date, still images or videos of real animals have been used in functional magnetic resonance imaging protocols to evaluate the brain activations associated with small animals' phobia. The objective of our study was to evaluate the brain activations associated with small animals' phobia through the use of virtual environments. This context will have the added benefit of allowing the subject to move and interact with the environment, giving the subject the illusion of being there. We have analyzed the brain activation in a group of phobic people while they navigated in a virtual environment that included the small animals that were the object of their phobia. We have found brain activation mainly in the left occipital inferior lobe (P<.05 corrected, cluster size=36), related to the enhanced visual attention to the phobic stimuli; and in the superior frontal gyrus (P<.005 uncorrected, cluster size=13), which is an area that has been previously related to the feeling of self-awareness. In our opinion, these results demonstrate that virtual stimulus can enhance brain activations consistent with previous studies with still images, but in an environment closer to the real situation the subject would face in their daily lives.
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