EFFECTS OF EMOTIONAL DISCRIMINATION TASKS ON CEREBRAL BLOOD-FLOW - REGIONAL ACTIVATION AND ITS RELATION TO PERFORMANCE

Facial discrimination tasks were applied as activation probes during p hysiologic neuroimaging (''neurobehavioral probes''). The stimuli pict ured professional actors and actresses, posing degrees of happy and sa d emotion. Cortical cerebral blood flow (CBF) was determined using the Xenon-133 inhalation method during resting baseline, two emotional (h appy from neutral and sad from neutral faces) and one nonemotional dis crimination task (age). The three tasks produced CBF increase over bas eline, which was greater in the right hemisphere (Task x Hemisphere in teraction, p = .0001). There were regionally specific effects (Task x Region x Hemisphere interaction, p = .022). Relative to the age discri mination task, both emotion discrimination tasks were associated with greater right parietal activation. In addition, the happy discriminati on task induced greater left frontal activation relative to the sad di scrimination task. While overall magnitude of CBF increase did not sho w regionally specific correlations with performance, laterality did sh ow such specificity. Sad discrimination performance correlated with gr eater right parietal activation, while performance on the happy discri mination task correlated with left frontal activation. Age discriminat ion performance correlated with higher activated right temporal CBF. T hese results support the hypothesis of right hemispheric involvement i n facial processing and further suggest regionally specific hemispheri c participation in happy and sad emotional discrimination. The study u nderscores the utility of performance measures for understanding the b ehavioral significance of activation effects in physiologic neuroimagi ng studies. (C) 1994 Academic Press, Inc.