Publications by authors named "Terrence Deacon"

The theory of Selected Effects (SE) is currently the most widely accepted etiological account of function in biology. It argues that the function of any trait is the effect that past traits of that type produced that contributed to its current existence. Its proper or etiological function is whatever effect was favoured by natural selection irrespective of the trait's current effects.

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We show how distinct terminally disposed self-organizing processes can be linked together so that they collectively suppress each other's self-undermining tendency despite also potentiating it to occur in a restricted way. In this way, each process produces the supportive and limiting boundary conditions for the other. The production of boundary conditions requires dynamical processes that decrease local entropy and increase local constraints.

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The brain is a living organ with distinct metabolic constraints. However, these constraints are typically considered as secondary or supportive of information processing which is primarily performed by neurons. The default operational definition of neural information processing is that (1) it is ultimately encoded as a change in individual neuronal firing rate as this correlates with the presentation of a peripheral stimulus, motor action or cognitive task.

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This paper describes an evolutionary process likely involved in hierarchic transitions in biological evolution at many levels, from genetics to social organization. It is related to the evolutionary process described as contingent neutral evolution (CNE). It involves a sequence of stages initiated by the spontaneous appearance of functional redundancy.

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We agree with Brette's assessment that the coding metaphor has become more problematic than helpful for theories of brain and cognitive functioning. In an effort to aid in constructing an alternative, we argue that joining the insights from the dynamical systems approach with the semiotic framework of C. S.

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Article Synopsis
  • The review addresses key philosophical challenges in origins-of-life research, including debates on the definitions of life and the methodologies for investigating its origins amid a lack of consensus on a universal theory.
  • It highlights important distinctions between different research approaches, such as synthetic, historical, and universal, while discussing the implications of the "bottom up" and "top down" strategies for understanding the first living entities and the last universal common ancestor.
  • The historical context of origins-of-life studies is explored, detailing influential figures and theories that have shaped the field, emphasizing how philosophical perspectives have evolved alongside scientific advancements.
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The origin of living dynamics required a local evasion of thermodynamic degradation by maintaining critical dynamical and structural constraints. Scenarios for life`s origin that fail to distinguish between constrained chemistry and regulated metabolism do not address the question of how living processes first emerge from simpler constraints on molecular interactions. We describe a molecular model system consisting of coupled reciprocal catalysis and self-assembly in which one of the catalytic bi-products tends to spontaneously self-assemble into a containing shell (analogous to a viral capsule).

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The classic anthropological hypothesis known as the "obstetrical dilemma" is a well-known explanation for human altriciality, a condition that has significant implications for human social and behavioral evolution. The hypothesis holds that antagonistic selection for a large neonatal brain and a narrow, bipedal-adapted birth canal poses a problem for childbirth; the hominin "solution" is to truncate gestation, resulting in an altricial neonate. This explanation for human altriciality based on pelvic constraints persists despite data linking human life history to that of other species.

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Explaining the extravagant complexity of the human language and our competence to acquire it has long posed challenges for natural selection theory. To answer his critics, Darwin turned to sexual selection to account for the extreme development of language. Many contemporary evolutionary theorists have invoked incredibly lucky mutation or some variant of the assimilation of acquired behaviors to innate predispositions in an effort to explain it.

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Article Synopsis
  • - Targeted delivery of drugs to specific CNS neurons is a major goal in improving treatment efficiency while minimizing side effects caused by systemic administration methods used for various medications.
  • - The researchers created a tripartite molecular system made up of an axonal transport facilitator, a polymer linker, and numerous drug molecules, allowing for effective drug delivery and active release inside the target neurons.
  • - Their findings showed that using this targeted delivery system significantly increased the effectiveness of gabapentin, showcasing a tenfold increase in its half-life and a 300-fold reduction in the required dosage compared to traditional methods.
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Deacon has recently proposed that complexes of genes can be integrated into functional groups as a result of environmental changes that mask and unmask selection pressures. For example, many animals endogenously synthesize ascorbic acid (vitamin C), but anthropoid primates have only a nonfunctional version of the crucial gene for this pathway. It is hypothesized that the loss of functionality occurred in the evolutionary past when a diet rich in vitamin C masked the effect of the gene, and its loss effectively trapped the animals in a fruit-eating lifestyle.

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The 'language-readiness' of human brains most probably resulted from modification of structures present in non-human primate brains, but identifying such homologues and the nature of their modifications has been highly problematic. In a recent article, Arbiband Bota suggest that these problems can be overcome using a neuroinformatics approach. But its assumptions ignore many non-local, activity-dependent, regressive, and allometric effects of neurodevelopment that violate assumptions of classic homology.

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