The Pineal-Hypothalamic Resonance Hypothesis

Executive cognitive functions display robust circadian variability, yet the mechanistic basis for circadian modulation of executive plasticity remains poorly characterized. This hypothesis proposes that pineal-derived melatonin and hypothalamic circadian signaling create a resonance window that dynamically reorganizes prefrontal-limbic connectivity across the sleep-wake cycle. We outline molecular, cellular, and systems-level mechanisms linking circadian oscillators to synaptic plasticity in executive circuits and provide testable predictions for neuroimaging and neurophysiological studies.