Dissociable temporal lobe activations during emotional episodic memory retrieval

The richness of human recollective experience is, in part, related to evoca tion of previously experienced emotions. An extensive functional neuroimagi ng literature has provided a description of brain regions involved in retri eving emotionally neutral episodic memories. Whether similar or distinct sy stems are involved in retrieving emotional memories is unresolved. This que stion motivated the present functional neuroimaging study, using 0-15 posit ron emission tomography (PET), where we compared patterns of brain activati on associated with retrieving previously studied emotional and neutral pict orial material. By varying task requirements and item density we characteri zed two distinct neural response patterns during emotional memory retrieval . First, we identified an anterior temporal pole activation that reflected the psychological set associated with emotional memory retrieval. Second, w e identified a left amygdala response sensitive to actual retrieval of emot ional items. These data suggest distinct functional roles for temporal lobe regions during emotional memory retrieval involving context-related tonic anterior temporal pole activation and a phasic item-related amygdala respon se. We conclude that brain regions involved in episodic memory retrieval re flect not only physical attributes of stimulus material, for example, their verbal or visual qualities, but also their affective significance. (C) 200 0 Academic Press.