Cortical midline structures and the self

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Abstract

For a long time philosophers and psychologists have been intrigued by the question of the self. More recently, this has become a topic of discussion in neuroscience. In this article, we suggest that the processing of self-referential stimuli in cortical midline structures (CMS) is a fundamental component in generating a model of the self. Drawing from neuroimaging studies, we distinguish between representation, monitoring, evaluation and integration of self-referential stimuli. All of these subfunctions are related to distinct regions within the CMS. This relationship between self-referential processing and CMS might provide novel insight into the neural correlates underlying the constitution of the self.

Section snippets

Domains of the self and lateral cortical regions

Although this article focuses on the CMS, several previous studies have associated lateral cortical regions with specific processes related to the self (Figure 1). These processes seem to involve predominantly the right hemisphere [9], in particular the right prefrontal 11, 13, 16 and parietal cortex. The feeling of being causally involved in an action has been referred to as ‘agency’. Agency is related to the right posterior insula and the right inferior parietal cortex [17], but also to CMS

Domains of the self and CMS

A remarkable variety of domains and cortical regions have been associated with the processing of the self. The constitution of the self might result from some kind of integration of these distinct domains. What is the thread linking the diverse processes related to the self? We argue that this is what Damasio 3, 5 calls the ‘core self’. Damasio relates the ‘core self’ to the continuous conjunction of intero- and exteroceptive stimuli leading to the experience of the self as a unit. Anatomically

Empirical findings: the processing of self-referential stimuli in the CMS

In the following, we review the current evidence in support of a link between CMS and the processing of self-referential stimuli. We distinguish between representation, monitoring, evaluation and integration of self-referential stimuli. We relate these psychological processes to specific regions within the CMS (Figure 2). Specifically, the orbitomedial prefrontal cortex (OMPFC) seems to account for the continuous representation of self-referential stimuli. Once represented in the OMPFC,

Process specificity in the CMS

In the case of the lateral prefrontal regions, the concepts of domain specificity and process specificity have been discussed in the literature [55]. Process specificity suggests a functional organization regarding specific psychological processes (such as storage and manipulation of information in working memory) in different regions, independently of the processed contents. By contrast, domain specificity reflects functional organization with regard to the content (such as verbal and spatial

Conclusions

Continously ongoing processing of self-referential stimuli might be considered a fundamental component in the constitution of a permanent self. We suggest that the processing of self-referential stimuli can be characterized by four subprocesses – representation, monitoring, evaluation and integration. These processes can be related to distinct regions within the CMS. This leads to the understanding of the CMS as a functional unit. The OMPFC may be considered as the ‘entrance door’ to the CMS

Acknowledgements

The writing of this article was supported by a Heisenberg grant from the German Research Foundation (DFG, 304/4–1) to G.N. and a grant from the German Academic Exchange Service (DAAD, D/02/46858) to F.B. We are grateful to our colleagues L. Merabet, C. Baethge and C. Muskopf for commenting critically on earlier versions of the manuscript.

References (60)

  • T.W. Kjaer

    Reflective self-awareness and conscious states: PET evidence for a common midline parietofrontal core

    Neuroimage

    (2002)
  • K.L. Phan

    Functional neuroanatomy of emotion: a meta-analysis of emotion activation studies in PET and fMRI

    Neuroimage

    (2002)
  • G. Bush

    Cognitive and emotional influences in anterior cingulate cortex

    Trends Cogn. Sci.

    (2000)
  • K. Vogeley

    Mind reading: neural mechanisms of theory of mind and self-perspective

    Neuroimage

    (2001)
  • S. Zysset

    The anterior frontomedian cortex and evaluative judgment: an fMRI study

    Neuroimage

    (2002)
  • J. Greene et al.

    How (and where) does moral judgment work?

    Trends Cogn. Sci.

    (2002)
  • E.K. Miller

    The prefrontal cortex: no simple matter

    Neuroimage

    (2000)
  • E.C. Ferstl et al.

    What does the frontomedian cortex contribute to language processing: coherence or theory of mind?

    Neuroimage

    (2002)
  • H.L. Gallagher et al.

    Functional imaging of ‘theory of mind’

    Trends Cogn. Sci.

    (2003)
  • T. Metzinger

    Being No One: The Self-Model Theory of Subjectivity

    (2003)
  • G. Northoff

    Philosophy of The Brain

    (2003)
  • A.R. Damasio

    Looking for Spinoza: Joy, Sorrow, and the Feeling Brain

    (2003)
  • P.S. Churchland

    Self-representation in nervous systems

    Science

    (2002)
  • A.R. Damasio

    The Feeling of What Happens: Body and Emotion in the Making of Consciousness

    (1999)
  • J.E. LeDoux

    Synaptic Self: How Our Brains Become Who We Are

    (2002)
  • B.L. Miller

    Neuroanatomy of the self: evidence from patients with frontotemporal dementia

    Neurology

    (2001)
  • D.T. Stuss et al.

    Adult clinical neuropsychology: lessons from studies of the frontal lobes

    Annu. Rev. Psychol.

    (2002)
  • A.N. Schore

    Affect Dysregulation and Disorders of the Self

    (2003)
  • I.M. Craik

    In search of the self. A PET study

    Psychol. Sci.

    (1999)
  • W.M. Kelley

    Finding the self? An event-related fMRI study

    J. Cogn. Neurosci.

    (2002)
  • Cited by (0)

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