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generating a model <strong>of</strong> the self within such neuronal structures.<br />

They suggest that the orbitomedial prefrontal cortex (OMPFC)<br />

accounts <strong>for</strong> the continuous representation and refl ection <strong>of</strong><br />

self- referential inputs from the body and the environment [4].<br />

Once represented in the OMPFC, self- referential in<strong>for</strong>mation<br />

appears to be monitored in the supragenual anterior cingulate<br />

cortex and evaluated in the dorsomedial prefrontal cortex [45].<br />

These functions might be complemented by the integration <strong>of</strong><br />

this in<strong>for</strong>mation in the emotional and autobiographical context<br />

<strong>of</strong> one’s own person; this latter function may be related to the<br />

posterior cingulate cortex.<br />

Whereas philosophers aim at defining a coherent and<br />

differentiated concept <strong>of</strong> the self, neuroscientists address<br />

questions like the following: How can we study self- related<br />

mental processes empirically, i.e. how can we reliably operationalize<br />

self- related processes? What are the neural correlates<br />

<strong>of</strong> self- related mental processes? A typical example <strong>for</strong> such<br />

an operationalization is a functional magnetic resonance<br />

imaging (fMRI) study by Kelley and colleagues [33]. In this<br />

study, participants were asked to judge trait adjectives (<strong>for</strong><br />

example, “polite”) as to whether they properly described<br />

the participants themselves (self- referential), the current US<br />

president (other- referential), or a given case (case- referential).<br />

Comparing the self- referential trials with the other- referential<br />

and case- referential trials allowed identifying brain areas<br />

particularly associated with self- referential processing. In this<br />

experiment, effects were observed in the above mentioned<br />

cortical midline structures. Like most, if not all, neuroimaging<br />

studies <strong>of</strong> the self, this experiment does not examine the self<br />

per se, but rather self- referential stimulus processing. Although<br />

study participants need to have a coherent model or construct<br />

<strong>of</strong> their own self (which is in some way composed <strong>of</strong> individual<br />

experiences, beliefs, preferences, and capacities) to per<strong>for</strong>m the<br />

task, the experiment does not explicitly focus on this model.<br />

Instead, the experiment examines how this model is implicitly<br />

used by the study participant to judge the self- referentiality <strong>of</strong><br />

the trait adjectives presented.<br />

Self- referential processing is a heterogeneous process,<br />

entailing a complex set <strong>of</strong> operations. Consequently, a large<br />

series <strong>of</strong> experiments is needed to identify the neural correlates<br />

underlying the specifi c subprocesses. On the one hand, these<br />

studies aim at disentangling self- referential processing from<br />

closely related processes, such as emotion processing [47], episodic<br />

memory [49], theory <strong>of</strong> mind [62], reward processing [19]<br />

and realness [57]. On the other hand, these studies examine<br />

self- referential processing in different domains. Besides the<br />

above mentioned personal trait judgement, these domains<br />

concern the centeredness <strong>of</strong> an individual’s multidimensional<br />

and multimodal space upon one’s body [63], the recognition<br />

<strong>of</strong> one’s own face [35], the experience that one’s own body<br />

and environment are perceived as closely related to one’s own<br />

self (ownership [11]), the feeling <strong>of</strong> being causally involved<br />

in an action [17], and the perception <strong>of</strong> signals <strong>of</strong> one’s own<br />

body, e.g., heart beat [9]. Evidently, these domains <strong>of</strong> selfreferential<br />

processing concern both automatic, pre- refl ective<br />

self- awareness and higher- order conscious self- refl ection.<br />

Strikingly, self- referential processing across these different<br />

domains consistently activates the cortical midline structures<br />

and connected subcortical brain areas [46].<br />

A. Heinz et al. / European Psychiatry 27 (2012) / supplement n°2 / S32-S43 S41<br />

The concept <strong>of</strong> the embodied self draws on the idea that<br />

the human self model is based on the continuous processing<br />

<strong>of</strong> internally generated inputs. At the physiological level, this<br />

continuous self- referential process may correspond to the high<br />

level <strong>of</strong> neural activity found in the cortical midline structures<br />

and connected subcortical areas during so- called resting conditions,<br />

such as viewing a blank screen [45]. This high level <strong>of</strong><br />

neural activity at “rest” (i.e., in the absence <strong>of</strong> externally- oriented<br />

tasks) has been characterized as the “physiological baseline” or<br />

“default mode” <strong>of</strong> the brain [20]. Given this high baseline activity,<br />

it comes as no surprise that cortical midline structures are mainly<br />

modulated by deactivation during non- self- referential tasks. This<br />

deactivation might refl ect the temporary eclipse <strong>of</strong> subjective<br />

experience during tasks with externally- oriented cognitive and<br />

behavioral demands.<br />

Although self- referential processing involves pre- refl ective,<br />

continuous, internally- directed processes, recent neuroimaging<br />

studies suggest a strong infl uence <strong>of</strong> social interaction<br />

and culture on these processes. Support <strong>for</strong> the link between<br />

self- referential processing and social interaction comes from<br />

neuroimaging studies showing a striking overlap between brain<br />

areas involved in referring to one’s own actions, sensations and<br />

emotions (and to those <strong>of</strong> others. So why are similar brain areas<br />

“used” <strong>for</strong> these two processes that seem to differ so much at<br />

fi rst glance? On the one hand, activation <strong>of</strong> the self- network<br />

during social cognition may refl ect simulations that translate<br />

the bodily, emotional and mental states <strong>of</strong> others into the<br />

neural language <strong>of</strong> our own states [34]. According to simulation<br />

theory, such simulations are used by humans to understand<br />

others’mental states. On the other hand, the pre- refl ective as<br />

well as the self- conscious relationship to one’s own bodily,<br />

emotional and mental states seems to be established (phylogenetically<br />

and ontogenetically) through social interaction. We<br />

seem to “learn” about such states through prelingual and lingual<br />

communication about these states when they occur in oneself<br />

or the other [58].<br />

Recent transcultural neuroimaging studies have demonstrated<br />

that one’s cultural background can infl uence the neural<br />

activity that underlies self- referential processing [21]. Similar<br />

to the above- mentioned study by Kelley and colleagues [33],<br />

a fMRI study from China [65] measured brain responses while<br />

study participants judged personal trait adjectives regarding<br />

“self”, “mother” or “a public person” and compared selfreferential<br />

processes between Western and Chinese subjects.<br />

In both groups, the medial prefrontal cortex and anterior<br />

cingulate cortex showed stronger activation in self- compared<br />

to other- judgements. In addition, mother- judgements (relative<br />

to other- judgements) activated the medial prefrontal cortex<br />

in Chinese but not in Western study participants. The authors<br />

suggest that these fi ndings might refl ect two distinct types <strong>of</strong><br />

self- representation, namely a “Western independent” type <strong>of</strong> self<br />

versus an “East Asian interdependent” type <strong>of</strong> self [65]. These<br />

fMRI fi ndings demonstrate how neuroimaging can be used to<br />

distinguish culture- sensitive from culture- invariant neural<br />

mechanisms <strong>of</strong> self- referential processing.<br />

Another cross- cultural fMRI study by Chiao and coworkers<br />

[8] focused on the infl uence <strong>of</strong> so- called individualistic versus<br />

collectivistic views on self- referential processing. Starting point<br />

<strong>of</strong> the study was the rough and preliminary distinction between<br />

<strong>Pro<strong>of</strong>s</strong>

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