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PHILOSOPHICAL CONSIDERATIONS ON THE HUMAN COGNITIVE AGING





(Skolnick, Andrew A. JAMA . Chicago: Apr 22, 1992). The later reduction means and causaly explain a part of aging. The subcause of this reduction-cause are the accumulation of the genetical or lesional alterations of mitocondrias, which are the main energetical resources of cells, which make them non-functional. That is, the reduction of the cellular energetical resources has a causal role in the explanation of aging, in general. In this moment, it is unclear if the mitocondria is the only energetical resource of the cell and is afirmed that a "method for preventing or slowing loss of cognitive function may be as simple as maintaining adequate blood glucose levels".




(Skolnick, Andrew A. JAMA, Chicago: Apr 22, 1992; Gold)

2. THE SPEED AND THE HUMAN COGNITIVE AGING

In accord with the hypothesis of Bartzokis, the speed has an important role in the explanation of cognitive aging. More precisely, the author refers at the speed of transmission of electrical signals trough the neuronsí axons. The speed would make it possible the integration of the information encoded distributively along and through the extended areas of some neuronal networks. The integration of information distributed along the areas of some extended neuronal networks is essential for the realization of the higher-order cognitive functions. Additionally, if not even alternatively, some scientists consider that, the stability that is represented by the state of brain between some biotemporal limits is in fact an equilibrium between some regenerative and degenerative processes. Regeneration can mean neurogenesis and synaptogenesis. Degeneration can mean apoptotic neuronal losses and/or qualitative deterioration of the brainís cells.

That is, on the one hand it is sustained a reduction of the speed of transmission of the potentials of action, therefore a negative change of the quality of interneuronal communication, on the other hand it is sustained an unbalance between the proportion of regeneration and that of degeneration. Certainly, all this facts are effects of some physiological causes and will have a biophysical and biochemical explanation, but maybe we will have also a need of a specific philosophical or philosophico-scientific interpretation. It seems that, the continuous diminution of the neuronal quantity and quality, the diminution of the speed of transmission of the electrical signals that is caused by some neuronal qualitative changes (of myelin sheath) as wel as the reduction of the interneuronal connections (of the number and of the density of synapses) have a fundamental role in the explanation of the neurocognitive aging.



Bartzokis postulated and argued that, on the speed of trasmission depend many capacities of the neurocognitive system: the quality of the interneuronal communication, the quality of integration of informations encoded distributedly on extended cortical spaces, and the temporal encoding of information. The induction of the same types of quantitative, qualitative, and relational changes in an artificial cognitive network, would have to mime the negative cognitive changes and trajectories associated with aging and with the degenerative disorders of the aging-related diseases.

Bartzokis relationed a fundamental neurocognitive hypothesis (about the importance of the syncrony in the higher cognitive functions) with the observations from the psychology of AD (memory deficits) and with neurobiologic observations and hypotheses about the characteristics of AD (extra and intraneuronal toxic deposits, neuronal losses etc.). Moreover, he provided detailed explanations of the concrete neurophysiological mechanims by which have place the neuroquantitative, the neuroqualitative, and the neurorelational negative changes. The toxicity and the programmed death have an important role in the case of neuronal death. In conformity with Bartzokisís model, the sheath of myelin have multiple functions: the saltatory conduction (by depolarization, hypopolarization, and hyperpolarization) and the increase of the transmission speed of electrical signals, but also a protective role.





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