Magnesium deficiency differentially modulates hippocampal and prefrontal oscillations and cardiac rhythms

Magnesium (Mg) is an essential cation critical for neuronal and cardiac homeostasis, principally by modulating N-methyl-d-aspartate (NMDA) receptor function. While magnesium deficiency (MgD) is known to impair memory and autonomic function, the systemic interplay remains poorly understood. As a preliminary step to investigating neural activity during memory tasks, this study investigated the effects of 3 weeks of MgD on neural activity patterns and cardiac function in rats. Simultaneous electrophysiological recordings from the dorsal hippocampus and medial prefrontal cortex, along with electrocardiogram and electromyogram (EMG) monitoring, revealed that MgD selectively altered neural oscillations without affecting cardiac function or sleep architecture. Notably, frequency-specific changes in local field potentials (LFPs) were most pronounced during quiet wakefulness under dark conditions. This excessive enhancement of gamma wave activity may contribute to memory impairment. This 3-week deficiency was characterized by altered neural excitability, which could lead to cognitive impairment and partial cardiac arrhythmia. Our findings demonstrate that spontaneous neural activity is altered even in the 3-week of MgD and support a model in which the deficiency progressively disrupts physiological regulation.