In this commentaryI evaluate the claim made byKeenan, Nelson, OÕConnor, and Pascual-Leone (2001) that since self-recognition results from right hemispheric activity, self-awareness too is likely to be produced by the activity of the same hemisphere. This reasoning is based on the assumption that self-recognition represents a valid operationalization of self-awareness; I present two views that challenge this rationale. Keenan et al. also support their claim with published evidence relating brain activityand self-awareness; I closelyexamine their analysis of one specific review of (...) literature and conclude that it appears to be biased. Finally, recent research suggests that inner speech (which is associated with left hemispheric activity) is linked to self-awareness—an observation that further casts doubt on the existence of a right hemispheric self-awareness. Ó 2002 Elsevier Science (USA). All rights reserved. (shrink)

In this article I will attempt to refute the claim that the mind is a radically emergent feature of the brain. First, the inter-related concepts of emergence, reducibility and constraint are considered, particularly as these ideas relate to hierarchical biological systems. The implications of radical emergence theories of the mind such as the one posited by Roger Sperry, are explored. I then argue that the failure of Sperry's model is based on the notion that consciousness arises as a radically emergent (...) feature ‘at the top command’ of a non-nested neurological hierarchy. An alternative model, one that avoids the dualism inherent in radical emergence theories, is offered in which the brain is described as producing a nested hierarchy of meaning and purpose that has no ‘top’ or ‘summit’. Finally, I will argue there remains a non-reducible aspect of consciousness that does not depend upon radical emergence theory, but rather on the mutual irreducibility of the subjective and objective points of view. This irreducible aspect of consciousness can be understood as the non-mysterious result of brain evolution and normal neural functioning. (shrink)

Transcranial Magnetic Stimulation is a technique that may aid researchers in their attempts to elucidate the underlying brain functions involved in consciousness. By employing TMS along with other neuroimaging methods and case studies, researchers may be aided in addressing their various hypotheses. Employing the ‘brain as mobile’ analogy, it may be possible to determine the individual contributions of single elements of the brain without upsetting the overall balance.

Two patients with cerebral commissurotomy were tested with visual input lateralized to left or right half of the visual field by an opaque hemifield screen set in the focal plane of an optical system mounted on a scleral contact lens which allowed prolonged exposure and ocular scanning of complex visual arrays. Key personal and affect-laden stimuli along with items for assessing general social knowledgability were presented among neutral unknowns in visual arrays with 4-9 choices. Selective manual and associated emotional responses (...) obtained from the minor hemisphere to pictures of subject's self, relatives, pets and belongings, and of public, historical and religious figures and personalities from the entertainment world revealed a characteristic social, political, personal and self-awareness comparable roughly to that of the major hemisphere of the same subject. (shrink)