Medial prefrontal cortex and self-referential mental activity: Relation to a default mode of brain function

Abstract

Medial prefrontal cortex (MPFC) is among those brain regions having the highest baseline metabolic activity at rest and one that exhibits decreases from this baseline across a wide variety of goal-directed behaviors in functional imaging studies. This high metabolic rate and this behavior suggest the existence of an organized mode of default brain function, elements of which may be either attenuated or enhanced. Extant data suggest that these MPFC regions may contribute to the neural instantiation of aspects of the multifaceted ''self.'' We explore this important concept by targeting and manipulating elements of MPFC default state activity. In this functional magnetic resonance imaging (fMRI) study, subjects made two judgments, one self-referential, the other not, in response to affectively normed pictures: pleasant vs. unpleasant (an internally cued condition, ICC) and indoors vs. outdoors (an externally cued condition, ECC). The ICC was preferentially associated with activity increases along the dorsal MPFC. These increases were accompanied by decreases in both active task conditions in ventral MPFC. These results support the view that dorsal and ventral MPFC are differentially influenced by attentiondemanding tasks and explicitly self-referential tasks. The presence of self-referential mental activity appears to be associated with increases from the baseline in dorsal MPFC. Reductions in ventral MPFC occurred consistent with the fact that attention-demanding tasks attenuate emotional processing. We posit that both selfreferential mental activity and emotional processing represent elements of the default state as represented by activity in MPFC. We suggest that a useful way to explore the neurobiology of the self is to explore the nature of default state activity.

Rapid effects of brief intensive cognitive-behavioral therapy on brain glucose metabolism in obsessive-compulsive disorder

“…[47][48][49] The aMCC, described as limbic motor cortex that governs response selection, 47 has been shown to be involved in conscious regulation of emotion. The aMCC is activated by several cognitive tasks that are required and emphasized in CBT for OCD: selective attention to one's own emotional responses, 50,51 mindful awareness of one's own emotional state, reappraisal of negative stimuli, 52 and suppression of arousal 53 and negative affect. 54 Efferent projections from the aMCC to the amygdala appear to modulate amygdala activity.…”

Task-dependent posterior cingulate activation in mild cognitive impairment

“…Empirical evidence implicates PCC involvement in a wide variety of functions, including attention (Mesulam, Nobre, Kim, Parrish, & Gitelman, 2001), processing of emotional stimuli (Cato et al, 2004;Maddock, Garrett, & Buonocore, 2003), and self-monitoring during a default resting state (Greicius, Srivastava, Reiss, & Menon, 2004;Gusnard, Akbudak, Shulman, & Raichle, 2001;Raichle et al, 2001). …”

Self-appraisal decisions evoke dissociated dorsal—ventral aMPFC networks

“…The anterior medial prefrontal cortex (aMPFC) comprises large-scale networks that are selectively engaged by appraisal of and decisions about self-relevant stimuli (Gusnard, Akbudak, Shulman, & Raichle, 2001;Macrae, Moran, Heatherton, Banfield, & Kelley, 2004;Northoff & Bermpohl, 2004;Zysset, Huber, Samson, Ferstl, & von Cramon, 2003). Specifically, functional magnetic resonance imaging (fMRI) paradigms requiring cognitively based appraisals of one's personal characteristics (Fossati et al, 2003;Johnson et al, 2002;Kelley et al, 2002;Schmitz, Kawahara, & Johnson, 2004;Schmitz, Rowley, Kawahara, & Johnson, In press) as well as one's subjective preference (Johnson et al, in press;Seger, Stone, & Keenan, 2004;Zysset, Huber, Ferstl, & von Cramon, 2002;Zysset et al, 2003) evoke widespread activation extending along the midline dorsal-ventral axis of the aMPFC.…”