Todd E. Feinberg

Where in the brain is the self

Localizing the self in the brain has been the goal of consciousness research for centuries. Recently, there has been an increase in attention to the localization of the self. Here we present data from patients suffering from a loss of self in an attempt to understand the neural correlates of consciousness. Focusing on delusional misidentification syndrome (DMS), we find that frontal regions, as well as the right hemisphere appear to play a significant role in DMS and DMS related disorders. These data are placed in the context of neuroimaging findings.

Brain imaging of the self - Conceptual, anatomical and methodological issues

In this paper we consider two major issues: conceptual-experimental approaches to the self, and the neuroanatomical substrate of the self. We distinguish content- and processed-based concepts of the self that entail different experimental strategies, and anatomically, we investigate the concept of midline structures in further detail and present a novel view on the anatomy of an integrated subcortical-cortical midline system. Presenting meta-analytic evidence, we show that the anterior paralimbic, e.g. midline, regions do indeed seem to be specific for self-specific stimuli. We conclude that future investigation of the self need to develop novel concepts that are more empirically plausible than those currently in use. Different concepts of self will require novel experimental designs that include, for example, the brains resting state activity as an independent variable. Modifications of both conceptual and anatomical dimensions will allow an empirically more plausible account of the relationship between brain and self.

The evolutionary and genetic origins of consciousness in the Cambrian Period over 500 million years ago

Vertebrates evolved in the Cambrian Period before 520 million years ago, but we do not know when or how consciousness arose in the history of the vertebrate brain. Here we propose multiple levels of isomorphic or somatotopic neural representations as an objective marker for sensory consciousness. All extant vertebrates have these, so we deduce that consciousness extends back to the groups origin. The first conscious sense may have been vision. Then vision, coupled with additional sensory systems derived from ectodermal placodes and neural crest, transformed primitive reflexive systems into image forming brains that map and perceive the external world and the bodys interior. We posit that the minimum requirement for sensory consciousness and qualia is a brain including a forebrain (but not necessarily a developed cerebral cortex/pallium), midbrain, and hindbrain. This brain must also have (1) hierarchical systems of intercommunicating, isomorphically organized, processing nuclei that extensively integrate the different senses into representations that emerge in upper levels of the neural hierarchy; and (2) a widespread reticular formation that integrates the sensory inputs and contributes to attention, awareness, and neural synchronization. We propose a two-step evolutionary history, in which the optic tectum was the original center of multi-sensory conscious perception (as in fish and amphibians: step 1), followed by a gradual shift of this center to the dorsal pallium or its cerebral cortex (in mammals, reptiles, birds: step 2). We address objections to the hypothesis and call for more studies of fish and amphibians. In our view, the lamprey has all the neural requisites and is likely the simplest extant vertebrate with sensory consciousness and qualia. Genes that pattern the proposed elements of consciousness (isomorphism, neural crest, placodes) have been identified in all vertebrates. Thus, consciousness is in the genes, some of which are already known.

Neuroontology, neurobiological naturalism, and consciousness: A challenge to scientific reduction and a solution

One of the great challenges to a science of consciousness is the inability to reduce critical features of consciousness to neural processes. In this paper I identify four neuroontologically irreducible features (NOIF) - referral of neural states, mental unity, qualia, and mental causation - defined as aspects of consciousness in which subjective experience is not wholly reducible to objectively observed or objectively understood neurons (ontological subjectivity). I next analyze the emergent and unique system properties of the neural hierarchy and argue that while the NOIF are indeed ontologically subjective, each of the NOIF individually can be explained by the unique architecture and functional properties of the neural hierarchy that lead to both emergent properties and their irreducibility in a manner that does not violate any known physical laws nor require any new physics or the application of physics to emergence or reduction beyond that normally applied to biology in general. I conclude that consciousness is a neurobiologically unique and local phenomenon that is specific to particular neural systems, a view that is consistent with both ontological subjectivity and biological naturalism. I call this position weakly emergent nonreductive physicalism or neurobiological naturalism.

Neuropathologies of the self: Clinical and anatomical features.

The neuropathologies of the self (NPS) are disorders of the self and identity that occur in association with neuropathology and include perturbations of the bodily, relational, and narrative self. Right, especially medial-frontal and orbitofrontal lesions, are associated with these conditions. The ego disequilibrium theory proposes this brain pathology causes a disturbance of ego boundaries and functions and the emergence of developmentally immature styles of thought, ego functioning, and psychological defenses including denial, projection, splitting, and fantasy that the NPS patient has in common with the child. I hypothesize that during brain development between approximately ages 3 and 7 immature defensive functions and fantasies tend to be replaced by mature defenses and the inhibition of fantasy a process that depends upon maturational processes within the right hemisphere. I propose a four-tiered model of the NPS that emphasizes a multifactorial approach and includes both negative and positive, bottom up and top down, and neuropsychological and psychological factors.

The nested neural hierarchy and the self

In spite of enormous recent interest in the neurobiology of the self, we currently have no global models of the brain that explain how its anatomical structure, connectivity, and physiological functioning create a unified self. In this article I present a triadic neurohierarchical model of the self that proposes that the self can be understood as the product of three hierarchical anatomical systems: The interoself system, the integrative self system, and the exterosensorimotor system. An analysis of these three systems and their functional features indicates that the neural hierarchy possesses features of both non-nested and nested hierarchies that are necessary for the creation of a unified consciousness and self. These functional properties also make the central nervous system a biologically unique entity unlike anything else in nature.

Neuropathologies of the self and the right hemisphere: a window into productive personal pathologies

The neuropathologies of the self (NPS; Figure ​Figure1)1) is a proposed broad grouping of various syndromes in which the common factors are that a demonstrable focal brain lesion(s) or dementia causes an alteration in the patients personal identity or personal relationships between the self and the world. The NPS may include many conditions (some of which are highlighted in the Figure ​Figure1)1) but some of the better known are the delusional misidentification syndromes (DMS; Capgras and Fregoli syndromes, DMS for the mirror image); somatoparaphrenia; and phantom boarder syndrome (Feinberg, 2001, 2009a,b, 2010, 2011a; Feinberg et al., 1999; Feinberg and Keenan, 2005). Figure 1 Based upon Feinberg (2010, 2011a); Vaillant (1977, 1992, 1993) and Cramer (1991, 2006). On the left is a hierarchical four-tiered model of representative factors contributing to some of the neuropathologies of the self. Some cognitive (level 1) deficits ...