Trends in Cognitive Sciences
Cortical midline structures and 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.
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