The Concept of "Single-Trial Adaptation" as an Evolutionarily Optimal Strategy of the Brain and Body

The Concept of "Single-Trial Adaptation" as an Evolutionarily Optimal Strategy of the Brain and Body The classical view of aging and declining plasticity as inevitable wear and tear fails to explain the systemic and coordinated nature of these processes. This paper proposes an energetic concept of single-trial adaptation, postulating that the organism implements an evolutionarily optimal strategy of switching between two fundamental operational modes throughout its lifespan. In youth, the energy-intensive 'Construction' mode dominates, characterized by high neuroplasticity and active formation of adaptive schemas in response to a novel environment. As experience accumulates and the environment stabilizes—when the predicted benefit of plasticity (D+plasticity) begins to consistently be outweighed by its costs (D-plasticity)—the system transitions to the energy-saving 'Exploitation' mode. This transition materializes through a coordinated program of molecular 'safeguards' (reduced BDNF, enhanced GABAergic inhibition, epigenetic consolidation), which raise the energy threshold for profound changes. A special role is assigned to intelligence (prefrontal cortex) as a unique cognitive override system, capable of initiating deliberate adaptation even in adulthood by reappraising subjective D+ and D- values. The concept integrates data from neuroscience, gerontology, and evolutionary biology, explaining phenomena such as 'super-agers,' cognitive reserve, and the evolutionary logic of reproduction as a systemic reset of adaptation. The theory opens prospects for developing strategies of managed flexibility and healthy longevity through conscious influence on the plasticity balance.