Functional dissociation of ventral frontal and dorsomedial default mode network components during resting state and emotional autobiographical recall

Summary

A striking dissociation exists within the brain's Default Mode Network, fundamental to human cognition. Neuroscience and Cognitive psychology reveal that while mind wandering involves the DMN, its components activate differently. Using resting state fMRI, functional brain connectivity studies show emotional autobiographical memory recall strongly engages dorsomedial regions like the prefrontal cortex and posterior cingulate. In contrast, the resting state, linked to spontaneous attention, activates a ventral frontal network, including the ventral striatum and anterior cingulate cortex. This functional dissociation offers crucial insights for psychology and mental health research topics.

Abstract

Humans spend a substantial share of their lives mind-wandering. This spontaneous thinking activity usually comprises autobiographical recall, emotional, and self-referential components. While neuroimaging studies have demonstrated that a specific brain "default mode network" (DMN) is consistently engaged by the "resting state" of the mind, the relative contribution of key cognitive components to DMN activity is still poorly understood. Here we used fMRI to investigate whether activity in neural components of the DMN can be differentially explained by active recall of relevant emotional autobiographical memories as compared with the resting state. Our study design combined emotional autobiographical memory, neutral memory and resting state conditions, separated by a serial subtraction control task. Shared patterns of activation in the DMN were observed in both emotional autobiographical and resting conditions, when compared with serial subtraction. Directly contrasting autobiographical and resting conditions demonstrated a striking dissociation within the DMN in that emotional autobiographical retrieval led to stronger activation of the dorsomedial core regions (medial prefrontal cortex, posterior cingulate cortex), whereas the resting state condition engaged a ventral frontal network (ventral striatum, subgenual and ventral anterior cingulate cortices) in addition to the IPL. Our results reveal an as yet unreported dissociation within the DMN. Whereas the dorsomedial component can be explained by emotional autobiographical memory, the ventral frontal one is predominantly associated with the resting state proper, possibly underlying fundamental motivational mechanisms engaged during spontaneous unconstrained ideation.

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