Nunez's description of the brain as a medium capable of wave propagation has provided some fundamental insights into its dynamics. This approach soon reaches the descriptive limits of the brain as a physical system, however. We point out some biological constraints which differentiate the brain from physical systems and we elaborate on its consequences for future research.

We believe that the task goal in voluntary movements provides meaning to existing information sources in the environment and determines, in a dynamic way, the use and relative importance of these different sources. This task-centered meaning bridges the apparent controversy between what information is available in principle (i.e., specification), and what information is perceived.

Research collaboration beyond national jurisdiction is one aspect of the globalisation of health research. It has potential to complement researchers in terms of research skills, equipment and lack of adequate numbers of potential research subjects. Collaboration at an equal level of partnership though desirable, may not be practicable. Sometimes, human research specimens must be transported from one country to other. Where this occurs, there should be clear understanding between the collaborating research institutions regarding issues of access and control of the (...) specimens as well as the duration of storage of specimens. The researchers have the duty to inform the research participants about specimen storage and transport across national boundaries. While obtaining informed consent from study subjects if specimens are to be stored beyond the life of the present study could be the ideal, there still remains significant challenges in a multi-cultural world. (shrink)

We prove that compactness is equivalent to the amalgamation property, provided the occurrence number of the logic is smaller than the first uncountable measurable cardinal. We also relate compactness to the existence of certain regular ultrafilters related to the logic and develop a general theory of compactness and its consequences. We also prove some combinatorial results of independent interest.

Traditionally, people were recognized as being dead using cardio-respiratory criteria: individuals who had permanently stopped breathing and whose heart had permanently stopped beating were dead. Technological developments in the middle of the twentieth century and the advent of the intensive care unit made it possible to sustain cardio-respiratory and other functions in patients with severe brain injury who previously would have lost such functions permanently shortly after sustaining a brain injury. What could and should physicians caring for such patients do? (...) Significant advances in human organ transplantation also played direct and indirect roles in discussions regarding the care of such patients. Because successful transplantation requires that organs be removed from cadavers shortly after death to avoid organ damage due to loss of oxygen, there has been keen interest in knowing precisely when people are dead so that organs could be removed. Criteria for declaring death using neurological criteria developed, and today a whole brain definition of death is widely used and recognized by all 50 states in the United States as an acceptable way to determine death. We explore the ongoing debate over definitions of death, particularly over brain death or death determined using neurological criteria, and the relationship between definitions of death and organ transplantation. (shrink)

In this paper we attempt to sharpen and to provide an answer to the question of when human beings first become conscious. Since it is relatively uncontentious that a capacity for raw sensation precedes and underpins all more sophisticated mental capacities, our question is tantamount to asking when human beings first have experiences with sensational content. Two interconnected features of our argument are crucial. First, we argue that experiences with sensational content are supervenient on facts about electrical activity in the (...) cerebral cortex which can be ascertained through EEG readings. Second, we isolate from other notions of a‘functioning brain’that which is required to underpin the view that a cortex is functioning in a way which could give rise to rudimentary conscious experiences. We investigate the development in the human fetus of the anatomical and chemical pathways which underpin cortical activity and the growth and maturation of the electrical circuitry specifically associated with sensational content in adult experience. We conclude that a fetus becomes conscious at about 30 to 35 weeks after conception; an answer based on a careful analysis of EEG readings at various stages of cortical development. Finally, we survey the possible ethical ramifications of our answer. (shrink)

ABSTRACT In this paper we attempt to sharpen and to provide an answer to the question of when human beings first become conscious. Since it is relatively uncontentious that a capacity for raw sensation precedes and underpins all more sophisticated mental capacities, our question is tantamount to asking when human beings first have experiences with sensational content. Two interconnected features of our argument are crucial. First, we argue that experiences with sensational content are supervenient on facts about electrical activity in (...) the cerebral cortex which can be ascertained through EEG readings. Second, we isolate from other notions of a‘functioning brain’that which is required to underpin the view that a cortex is functioning in a way which could give rise to rudimentary conscious experiences. We investigate the development in the human fetus of the anatomical and chemical pathways which underpin (immature) cortical activity and the growth and maturation of the electrical circuitry specifically associated with sensational content in adult experience. We conclude (tentatively) that a fetus becomes conscious at about 30 to 35 weeks after conception; an answer based on a careful analysis of EEG readings at various stages of cortical development. Finally, we survey the possible ethical ramifications of our answer. (shrink)

The essays collected together in this volume, many of them written by leading scholars in the field, explore the commonsensical fact that our presence as..