Extended amygdala and emotional salience: A PET activation study of positive and negative affect

Functionalneuroimaging studies have implicated amygdaloid and basalforebrain regions, including sublenticular extended amygdala (SLEA), in the mediation of aversive emotionalresponses. However, it is not clear whether SLEA responds to ‘aversiveness’ orto generalstimulus salience. We predicted that both pleasant and aversive stimuliwouldactivatethis region. Using [₁₅O] water PET, we studied 10healthy subjects while viewing pleasant, aversive, neutral, and blank images. Each subject underwent eight scans, which were processedand averaged with standard statisticalmethods. Both positive and negative stimuliactivated regions in SLEA. Both positive and negativecontent activated the visualcortex, relative to neutralcontent. Aversive stimulideactivated the left frontal pole, relative to positive andneutralstimuli. These findings demonstrate that both positive and negative emotionalcontent evokes processing in the sublenticular/extended amygdala region, suggesting that this region is involved in generalemotionalprocessing, such as detection or attribution ofsalience.