Selective resilience in brain aging: challenging the scope of the disposable soma theory.

The disposable soma theory (DST) posits that organisms prioritize reproductive success over long-term somatic maintenance, resulting in an inevitable decline after reproduction. However, such a basis does not fully explain the human brain's capacity to preserve metabolically costly, plastic, and cognitively essential functions well beyond the reproductive peak. This Perspective challenges the universality of DST by proposing that brain aging follows a selectively resilient trajectory, shaped by post-reproductive adaptive pressures. Rather than depicting brain aging as passive deterioration, this work reinterprets it as an active and dynamic reallocation of energy and resources under systemic decline. Molecular and biochemical adaptations, such as ketone body metabolism, nicotinamide adenine dinucleotide (NAD⁺) salvage, alternative antioxidant defenses, and persistent estrogenic sensitivity, are presented as integrated strategies that ensure the selective preservation of neuronal functions. This article offers a revised theoretical lens that emphasizes adaptation, regional prioritization, and energetic economy across the lifespan, challenging some postulates of the DST.