Temporal precedence of emotion over attention modulations in the lateral amygdala: Intracranial ERP evidence from a patient with temporal lobe epilepsy
Previous fMRI studies have reported mixed evidence for the influence of selective attention on amygdala responses to emotional stimuli, with some studies showing "automatic" emotional effects to threat-related stimuli without attention (or even without awareness), but other studies showing a gating of amygdala activity by selective attention with no response to unattended stimuli. We recorded intracranial local field potentials from the intact left lateral amygdala in a human patient prior to surgery for epilepsy and tested, with a millisecond time resolution, for neural responses to fearful faces appearing at either task-relevant or task-irrelevant locations. Our results revealed an early emotional effect in the amygdala arising prior to, and independently of, attentional modulation. However, at a later latency, we found a significant modulation of the differential emotional response when attention was directed toward or away from fearful faces. These results suggest separate influences of emotion and attention on amygdala activation and may help reconcile previous discrepancies concerning the relative responsiveness of the human amygdala to emotional and attentional factors
