Motivational significance and cognitive effort elicit different late positive potentials

The interaction between affective and cognitive processes has been examined using the late positive potential (LPP) component of the event-related brain potential. The LPP is elicited not only by affective stimuli but also by nonaffective stimuli that require effortful cognitive processing. However, it is unclear whether these LPPs are equivalent. The present study decomposed the LPP into subcomponents that responded differently to affective content and cognitive demands.

The participants (N=21) performed four types of revised oddball tasks, in which one affective and five nonaffective pictures were presented. For one of the nonaffective pictures, different cognitive demands were loaded: viewing the display, updating a count, updating two different items, or concealing knowledge of the picture.

A temporal-spatial principal component analysis revealed two major subcomponents of the LPP. The central-parietal subcomponent was elicited by affective stimuli, whereas the occipital subcomponent was elicited by nonaffective stimuli with cognitive demands in the two-item updating and concealment conditions.

The results suggest that the central-parietal dominant LPP may reflect motivated attentional processing, whereas the occipital dominant LPP may reflect effortful controlled processing.

Dealing with these two LPP subcomponents separately may be useful for examining the interaction between affective and cognitive processing of stimuli.