Narrative imagery: Emotional modulation in the default mode network.

Imagining pleasant events activates the medial prefrontal cortex more than imagining unpleasant ones, while both pleasant and unpleasant imagery produce stronger activity in several default mode network (DMN) regions compared to neutral imagery. The study used a within-subject design to identify each person's DMN during rest and then measured brain activity during pleasant, neutral, or unpleasant narrative imagery. Enhanced activation for emotional versus neutral content appeared in the posterior cingulate cortex, angular gyrus, anterior hippocampus, lateral temporal cortex, temporal pole, dorsomedial prefrontal cortex, and ventrolateral prefrontal cortex. Widespread emotional modulation across the DMN suggests that retrieving and constructing events serves to simulate motivationally relevant experiences for adaptive planning.

Study at a glance

Abstract

The default mode network (DMN) is activated when constructing and imagining narrative events, with functional brain activity in one region, the medial-prefrontal cortex, hypothesized to be modulated during emotional processing by adding value (or pleasure) to the episodic representation. However, since enhanced reactivity during emotional, compared to neutral, content is a more frequent finding in both the brain and body in physiological, neural, and behavioral measures, the current study directly assesses the effects of pleasure and emotion during narrative imagery in the DMN by using a within-subject design to first identify the DMN during resting state and then assess activation during pleasant, neutral, or unpleasant imagery. Replicating previous findings, enhanced functional activity in the medial prefrontal cortex was found when imagining pleasant, compared to unpleasant, events. In addition, emotion-related activation was found when imagining either pleasant or unpleasant, compared to neutral, events, in other nodes of the DMN including the posterior cingulate cortex (PCC), angular gyrus, anterior hippocampus, lateral temporal cortex, temporal pole, dorsomedial prefrontal cortex (dmPFC), and ventrolateral prefrontal cortex (vlPFC). Pervasive emotional modulation in the DMN is consistent with the view that a primary function of event retrieval and construction is to remember, recreate, and imagine motivationally relevant events important for planning adaptive behavior.