Emotions are generally thought to arise through the interaction of bottom-up and top-down processes. However, prior work has not delineated their relative contributions. In a sample of 20 females, we used functional magnetic resonance imaging to compare the neural correlates of negative emotions generated by the bottom-up perception of aversive images and by the top-down interpretation of neutral images as aversive. We found that (a) both types of responses activated the amygdala, although bottom-up responses did so more strongly; (b) bottom-up responses activated systems for attending to and encoding perceptual and affective stimulus properties, whereas top-down responses activated prefrontal regions that represent high-level cognitive interpretations; and (c) self-reported affect correlated with activity in the amygdala during bottom-up responding and with activity in the medial prefrontal cortex during top-down responding. These findings provide a neural foundation for emotion theories that posit multiple kinds of appraisal processes and help to clarify mechanisms underlying clinically relevant forms of emotion dysregulation.
Friday, November 13, 2009
How you feel - the brain's bottom up and top down pathways
Ochsner et al use MRI to examine what is now becoming a common distinction, to consider the extent to which emotions arise via low-level processes that provide quick, bottom-up affective analyses of stimuli, versus high-level, top-down cognitive appraisal processes that draw upon stored knowledge. They did this by examining responses in trials with normatively aversive images (bottom-up trials) and also in novel trials in which participants cognitively interpreted neutral images as aversive (top-down trials). Here is the abstract, followed by a summary figure.