A positron emission tomographic study of simple phobic symptom provocation.

ABSTRACT

BACKGROUND: The goal of this study was to determine the mediating neuroanatomy of simple phobic symptoms. METHODS: Positron emission tomography and oxygen 15 were used to measure normalized regional cerebral blood flow in seven subjects with simple phobia during control and provoked states. Stereotactic transformation and statistical parametric mapping techniques were employed to determine the locations of significant activation. RESULTS: Statistical parametric maps demonstrated significant increases in normalized regional blood flow for the symptomatic state compared with the control state in the anterior cingulate cortex, the insular cortex, the anterior temporal cortex, the somatosensory cortex, the posterior medial orbitofrontal cortex, and the thalamus. CONCLUSIONS: The results suggest that anxiety associated with the simple phobic symptomatic state is mediated by paralimbic structures. Moreover, activation of somatosensory cortex may reflect tactile imagery as one component of the phobic symptomatic condition.