Tuesday, September 17, 2013

Looking for the "Self" in the Brain - Recent Developments

In the title of this post, I purposely placed self in quotation marks, for the simple reason that self (as most people conceive of it) is a transient experience and not an objective, measurable entity.

Despite the fact that neuroscience (aside from Buddhism) has done the most to dispel the self illusion, researchers continue to seek neural correlates of "self" in the brain. Below are the titles and abstracts of four such recent articles, all of which are interesting and informative.

I suspect that the future of this endeavor will move toward looking for the processes that generate the illusion of the singular self, while the various regions of the brain active in the process of "selfing" will become less important.

All of these article come from Frontiers in Human Neuroscience, an open source publisher of scientific research. The third paper below is from Antonio Damasio's lab and deals with the autobiographical self - I will post on this paper individually in the near future.

Self-processing and the default mode network: interactions with the mirror neuron system

Istvan Molnar-Szakacs [1,2] and Lucina Q. Uddin [3,4]
1. Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA
2. Tennenbaum Center for the Biology of Creativity, University of California, Los Angeles, CA, USA
3. Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
4. Department of Psychology, University of Miami, Coral Gables, FL, USA
Recent evidence for the fractionation of the default mode network (DMN) into functionally distinguishable subdivisions with unique patterns of connectivity calls for a reconceptualization of the relationship between this network and self-referential processing. Advances in resting-state functional connectivity analyses are beginning to reveal increasingly complex patterns of organization within the key nodes of the DMN – medial prefrontal cortex and posterior cingulate cortex – as well as between these nodes and other brain systems. Here we review recent examinations of the relationships between the DMN and various aspects of self-relevant and social-cognitive processing in light of emerging evidence for heterogeneity within this network. Drawing from a rapidly evolving social-cognitive neuroscience literature, we propose that embodied simulation and mentalizing are processes which allow us to gain insight into another’s physical and mental state by providing privileged access to our own physical and mental states. Embodiment implies that the same neural systems are engaged for self- and other-understanding through a simulation mechanism, while mentalizing refers to the use of high-level conceptual information to make inferences about the mental states of self and others. These mechanisms work together to provide a coherent representation of the self and by extension, of others. Nodes of the DMN selectively interact with brain systems for embodiment and mentalizing, including the mirror neuron system, to produce appropriate mappings in the service of social-cognitive demands.
Full Citation: 
Molnar-Szakacs I and Uddin LQ. (2013, Sep 11). Self-processing and the default mode network: interactions with the mirror neuron system. Frontiers in Human Neuroscience; 7:571. doi: 10.3389/fnhum.2013.00571

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Looking for the self in pathological unconsciousness

Athena Demertzi [1], Audrey Vanhaudenhuyse [1], Serge Brédart [2], Lizette Heine [1], Carol di Perri [3] and Steven Laureys [1]
1. Coma Science Group, Cyclotron Research Center and Neurology Department, University of Liège, Liège, Belgium
2. Department of Psychology, Behavior, and Cognition, University of Liège, Liège, Belgium
3. Department of Neuroradiology, National Neurological Institute C. Mondino, Pavia, Italy
There is an intimate relationship between consciousness and the notion of self. By studying patients with disorders of consciousness, we are offered with a unique lesion approach to tackle the neural correlates of self in the absence of subjective reports. Studies employing neuroimaging techniques point to the critical involvement of midline anterior and posterior cortices in response to the passive presentation of self-referential stimuli, such as the patient’s own name and own face. Also, resting state studies show that these midline regions are severely impaired as a function of the level of consciousness. Theoretical frameworks combining all this progress surpass the functional localization of self-related cognition and suggest a dynamic system-level approach to the phenomenological complexity of subjectivity. Importantly for non-communicating patients suffering from disorders of consciousness, the clinical translation of these technologies will allow medical professionals and families to better comprehend these disorders and plan efficient medical management for these patients.
Full Citation: 
Demertzi A, Vanhaudenhuyse A, Brédart S, Heine L, di Perri C and Laureys S. (2013, Sep 3). Looking for the self in pathological unconsciousness. Frontiers in Human Neuroscience; 7:538. doi: 10.3389/fnhum.2013.00538

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Cortical midline structures and autobiographical-self processes: an activation-likelihood estimation meta-analysis

Helder F. Araujo [1,2,3], Jonas Kaplan [1] and Antonio Damasio [1] 
1. Brain and Creativity Institute, University of Southern California, Los Angeles, CA, USA
2. Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
3. Graduate Program in Areas of Basic and Applied Biology, University of Oporto, Oporto, Portugal
The autobiographical-self refers to a mental state derived from the retrieval and assembly of memories regarding one’s biography. The process of retrieval and assembly, which can focus on biographical facts or personality traits or some combination thereof, is likely to vary according to the domain chosen for an experiment. To date, the investigation of the neural basis of this process has largely focused on the domain of personality traits using paradigms that contrasted the evaluation of one’s traits (self-traits) with those of another person’s (other-traits). This has led to the suggestion that cortical midline structures (CMSs) are specifically related to self states. Here, with the goal of testing this suggestion, we conducted activation-likelihood estimation (ALE) meta-analyses based on data from 28 neuroimaging studies. The ALE results show that both self-traits and other-traits engage CMSs; however, the engagement of medial prefrontal cortex is greater for self-traits than for other-traits, while the posteromedial cortex is more engaged for other-traits than for self-traits. These findings suggest that the involvement CMSs is not specific to the evaluation of one’s own traits, but also occurs during the evaluation of another person’s traits.
Full Citation: 
Araujo HF, Kaplan J and Damasio A. (2013, Sep 4). Cortical midline structures and autobiographical-self processes: an activation-likelihood estimation meta-analysis. Frontiers in Human Neuroscience; 7:548. doi: 10.3389/fnhum.2013.00548

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A philosophical perspective on the relation between cortical midline structures and the self

Kristina Musholt 
Department of Philosophy, Logic and Scientific Method, London School of Economics and Political Science, London, UK
In recent years there has been increasing evidence that an area in the brain called the cortical midline structures (CMSs) is implicated in what has been termed self-related processing. This article will discuss recent evidence for the relation between CMS and self-consciousness in light of several important philosophical distinctions. First, we should distinguish between being a self (i.e., being a subject of conscious experience) and being aware of being a self (i.e., being able to think about oneself as such). While the former consists in having a first-person perspective on the world, the latter requires the ability to explicitly represent one’s own perspective as such. Further, we should distinguish between being aware of oneself “as subject” and being aware of oneself “as object.” The focus of existing studies investigating the relation between CMS and self has been predominantly on the ability to think about oneself (and in particular thinking of oneself “as object”), while the more basic aspects involved in being a self have been neglected. However, it is important to widen the scope of the cognitive neuroscience to include the latter, not least because this might have important implications for a better understanding of disorders of the self, such as those involved in schizophrenia. In order to do so, cognitive neuroscience should work together with philosophy, including phenomenology. Second, we need to distinguish between personal and subpersonal level explanations. It will be argued that although it is important to respect this distinction, in principle, some subpersonal facts can enter into constitutive conditions of personal-level phenomena. However, in order for this to be possible, one needs both careful conceptual analysis and knowledge about relevant cognitive mechanisms.
Full Citation: 
Musholt K. (2013, Sep 2). A philosophical perspective on the relation between cortical midline structures and the self. Frontiers in Human Neuroscience; 7:536. doi: 10.3389/fnhum.2013.00536
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