ANTERIOR PARALIMBIC MEDIATION OF PROCAINE-INDUCED EMOTIONAL AND PSYCHOSENSORY EXPERIENCES

Background: Procaine activates limbic structures in animals. In humans , acute intravenous administration of procaine fields emotional and ps ychosensory experiences and temporal lobe fast activity. We studied pr ocaine's acute effects on cerebral blood flow (CBF) in relationship to clinical responses. Methods: Cerebral blood flow was assessed by posi tron emission tomography with oxygen-15-labeled water in 32 healthy vo lunteers. Data were analyzed with statistical parametric mapping and m agnetic resonance imaging-directed regions of interest. Results: Proca ine increased global CBF and, to a greater extent, anterior paralimbic CBF. Subjects with intense procaine-induced fear compared with those with euphoria had greater increases in left amygdalar CBF. Absolute an d normalized left amygdalar CBF changes tended to correlate positively with fear and negatively with euphoria intensity. Procaine-induced vi sual hallucinations appeared associated with greater global and occipi tal CBF increases. Absolute occipital CBF increases appeared to correl ate positively with visual hallucination intensity. Conclusions: Proca ine increased anterior paralimbic CBF, and different clinical response s appeared to be associated with different patterns of CBF changes.