Neural mechanisms and time-course of emotional attention

Vuilleumier, P.
Neurology & Imaging of Cognition, Department of Neuroscience & Physiology, University of Geneva, Switzerland

Emotional information can influence the processing of visual stimuli, especially based on their fear-related significance. Behavioral and functional neuroimaging studies in healthy subjects and brain-damaged patients converge to demonstrate that attention is preferentially biased towards fearful rather than neutral faces. Such effects appear to be mediated by rapid enhancement of sensory responses in fusiform and earlier visual cortical areas, through modulatory influences from amygdala that are partly independent of voluntary mechanisms of attention. Emotional responses in amygdala can be elicited rapidly by coarse cues based on low spatial frequency information in faces, whereas cortical fusiform areas involved in conscious face perception might operate more slowly, tuned to extract finer visual features. Evoked potentials and source localization techniques also show an early modulation of extrastriate areas in response to fearful faces, with a similar time-course and substrate as other exogenous effects in spatial attention. Thus, face perception involves a dynamic interplay between distant brain regions exerting reciprocal modulatory influences on each other, and mechanisms of emotional attention may influence sensory processing in ways that are similar but partly independent of other mechanisms of spatial attention.