The nature of consciousness

Do some people with a prolonged disorder of consciousness experience pain? A clinically focused narrative review and synthesis

ObjectiveTo investigate the hypothesis that people with a prolonged disorder of consciousness experience nociceptive pain.MethodA non-systematic literature review into the nature and neurophysiological basis of consciousness and pain likely function when someone has severe thalamocortical dysfunction; the behavioural manifestations of pain in people who cannot communicate; and how they relate to the experience.FindingsConsciousness depends on thalamocortical integrity and is judged clinically by establishing the person's behaviour depends on extracting or using meaning. The experience of pain is also deduced from a person's behaviour, including increased purposeless motor movements, facial expressions, non-verbal vocal expressions and physiological (autonomic) changes such as tachycardia and tear production. Extensive brainstem and midbrain networks are activated by pain, including autonomic networks. Given their early evolution and location, they likely resist damage. The networks appear intrinsically resilient, functioning when damaged unless the damage is severe.SynthesisSomeone with a prolonged disorder of consciousness usually has intransitive consciousness (arousal) that is not dependent on cortical cognitive processes and may have retained occurrent consciousness of mental states when aroused. Nociceptive stimuli elicit automatic but purposeless behaviours typically associated with pain. These behaviours are likely to be responses to this unpleasant mental state of occurrent consciousness that is limited to the time they show pain behaviours, with no memory of it.ConclusionThe unconscious person with a prolonged disorder of consciousness exhibiting pain behaviours in response to nociceptive stimuli likely experiences pain without analysing its significance; they are unlikely to anticipate or remember it.

Implications of John Kavanaugh's Philosophy of the Human Person as Embodied Reflexive Consciousness for Conscientious Decision-making in Brain Death

This article reviews the work of Fr. John F. Kavanaugh, SJ (1941-2012), on the human person as embodied reflexive consciousness (RC). It then analyzes the implications of his work for the subject of brain death. Case studies are reviewed which suggest that RC persists unchanged in the setting of substantial brain trauma. RC is posited as an immaterial endowment, rather than a material phenomenon, which is fully present so long as a person is alive and becomes absent when a person is truly dead. As the endowment which makes possible ethical action and is common to all human persons, RC becomes the foundation of human equality. Empirically ascertaining the presence or absence of RC may not be possible-its demonstration may be precluded by physical immaturity or damage. Therefore, until the human person (and not only the brain) has wholly and irreversibly died, RC should be assumed to be present. The current criteria for brain death are incapable of ensuring that the entire brain has permanently and irreversibly ceased to function. Therefore, RC may still be present in those whose organs are harvested after meeting the criteria for brain death. As such, a human person would still be present, albeit a wounded human person. Based on this, a healthcare provider could (and likely should) in good conscience oppose the use of brain death criteria for purposes of harvesting vital organs. On a societal level, utilizing brain death criteria to declare a person dead has the potential in any given case to violate the dead donor rule, and as such conflicts with the widely held moral consensus that organs should only be harvested from those who are dead. Healthcare providers should advocate for medicolegal frameworks consistent with their informed consciences.

Time models and cognitive processes: a review

The sense of time is an essential capacity of humans, with a major role in many of the cognitive processes expressed in our daily lifes. So far, in cognitive science and robotics research, mental capacities have been investigated in a theoretical and modeling framework that largely neglects the flow of time. Only recently there has been a rather limited, but constantly increasing interest in the temporal aspects of cognition, integrating time into a range of different models of perceptuo-motor capacities. The current paper aims to review existing works in the field and suggest directions for fruitful future work. This is particularly important for the newly developed field of artificial temporal cognition that is expected to significantly contribute in the development of sophisticated artificial agents seamlessly integrated into human societies.