The personal identity relation is of great interest to philosophers, who often consider fictional scenarios to test what features seem to make persons persist through time. But often real examples of neuroscientific interest also provide important tests of personal identity. One such example is the case of Phineas Gage – or at least the story often told about Phineas Gage. Many cite Gage’s story as example of severed personal identity; Phineas underwent such a tremendous change that Gage “survived as a (...) different man.” I discuss a recent empirical finding about judgments about this hypothetical. It is not just the magnitude of the change that affects identity judgment; it is also the negative direction of the change. I present an experiment suggesting that direction of change also affects neuroethical judgments. I conclude we should consider carefully the way in which improvements and deteriorations affect attributions of personal identity. This is particularly important since a number of the most crucial neuroethical decisions involve varieties of cognitive enhancements or deteriorations. (shrink)

Different anesthetics are known to modulate different types of membrane-bound receptors. Their common mechanism of action is expected to alter the mechanism for consciousness. Consciousness is hypothesized as the integral of all the units of internal sensations induced by reactivation of inter-postsynaptic membrane functional LINKs during mechanisms that lead to oscillating potentials. The thermodynamics of the spontaneous lateral curvature of lipid membranes induced by lipophilic anesthetics can lead to the formation of non-specific inter-postsynaptic membrane functional LINKs by different mechanisms. These (...) include direct membrane contact by excluding the inter-membrane hydrophilic region and readily reversible partial membrane hemifusion. The constant reorganization of the lipid membranes at the lateral edges of the postsynaptic terminals (dendritic spines) resulting from AMPA receptor-subunit vesicle exocytosis and endocytosis can favor the effect of anesthetic molecules on lipid membranes at this location. Induction of a large number of non-specific LINKs can alter the conformation of the integral of the units of internal sensations that maintain consciousness. Anesthetic requirement is reduced in the presence of dopamine that causes enlargement of dendritic spines. Externally applied pressure can transduce from the middle ear through the perilymph, cerebrospinal fluid, and the recently discovered glymphatic pathway to the extracellular matrix space, and finally to the paravenular space. The pressure gradient reduce solubility and displace anesthetic molecules from the membranes into the paravenular space, explaining the pressure reversal of anesthesia. Changes in membrane composition and the conversion of membrane hemifusion to fusion due to defects in the checkpoint mechanisms can lead to cytoplasmic content mixing between neurons and cause neurodegenerative changes. The common mechanism of anesthetics presented here can operate along with the known specific actions of different anesthetics. (shrink)

Neuroplasticity, the capacity of the brain to induce changes in response to environmental stimuli, entails a continuous rearrangement of the neural network through a complex interaction between genetics and environment. Within this process, the plastic brain uses its internal representations to predict future conditions and proactively proceed to actions. It can be said that plasticity demands a rethinking of the concept of determinism as the process of coming-to-be is directly related to modifications produced by experience. Pure determinism and complete randomness (...) are the two ends of a spectrum of positions relevant to the debate of the existence of free will. However, none conceptually supports free decision-making. How brain activity and the conscious experience of volition are related to one another has been a matter of significant research, with a plethora of findings indicating that early brain signals precede the self-reported time of the decision to act. The meaning of these findings, however, has been debated at both a theoretical and empirical level and the controversy is still ongoing. Consciousness is intertwined with free will along the dimension of time as it would otherwise be purposeless, taking place right at the next moment. Electrical activity of the brain is a measure of neurophysiological function and contributes to the understanding of processes that underlie high-order cognitive functions. A multidisciplinary approach in the study of free will could be designed in a way that philosophical concepts are connected to neural correlates by psychologically functionalizing them in terms of cognitive abilities. Such abilities are at the margins of conscious and nonconscious sensory information and are closely linked to brain processes of executive functions like attentional control and working memory. (shrink)