Neuropharmacology of synaptic plasticity: pathways to cognitive resilience in healthy aging.

The aging process is associated with gradual cognitive decline resulting from deficits in synaptic plasticity, the brain's natural ability to adapt and reshape its neural circuitry. This review highlights the importance of synaptic plasticity in cognitive function. It provides a full overview of the molecular, cellular, and systemic mechanisms involved in enhanced or diminished synaptic plasticity in the aging brain. We also go over issues in neurotransmitter systems, calcium signaling, neurotrophic support (ex., BDNF-TrkB), cellular signaling pathways (e.g. mTOR, CaMK, CREB, and MAPK/ERK), and neuroinflammation, oxidative stress, and vascular integrity, all of which redirect the trajectory of synaptic failure associated with cognitive decline in aging. Therapeutic approaches toward increasing or restoring synaptic plasticity are evaluated, including pharmacological (e.g., nootropics, cholinesterase inhibitors, NMDA receptor modulators), natural (e.g., curcumin, resveratrol, bacoside A), and new interventions (e.g., psychoplastogens, gene therapy, nanocarriers, and digital therapeutics). Lifestyle approaches, especially physical exercise, cognitive training, intermittent fasting, and mindfulness approaches to stimulation, have highly potent effects on plasticity enhancements and employ multiple neurobiological mechanisms. Despite much promise, there remain substantial translational challenges, including limited clinical efficacy, lack of personalized biomarkers, and ethical considerations concerning cognitive enhancement. As we look ahead, a multidisciplinary integrative approach that includes molecular therapeutics, lifestyle interventions, and next-generation neurotechnologies will be most useful for protecting cognitive health and enhancing brain resilience in aging individuals. This review highlights the immediate necessity for personalized, ethical, and evidence-based approaches to take advantage of synaptic plasticity for healthy cognitive aging.