# Vocabulary: Magnesium, NMDA Receptors and Learning Back to [[Topics/Magnesium, NMDA Receptors and Learning/Magnesium, NMDA Receptors and Learning|hub]]. - **NMDA receptor (NMDAR):** a glutamate-gated ion channel in neurons, named after the synthetic agonist N-methyl-D-aspartate. It lets in Ca²⁺ as well as Na⁺, and is central to synaptic plasticity. - **Glutamate:** the brain's main excitatory neurotransmitter. - **Co-agonist (glycine / D-serine):** a second molecule that must bind alongside glutamate for the NMDA receptor to open. - **Magnesium (Mg²⁺) block:** extracellular Mg²⁺ sits in the NMDA channel pore at resting voltage and stops current flowing. - **Voltage dependence:** the block weakens as the membrane becomes less negative (depolarized), so the channel conducts only when glutamate binding and depolarization coincide. - **Depolarization:** the inside of the membrane becoming less negative, from synaptic input or back-propagating action potentials. - **Coincidence detector:** something that responds only when two signals arrive together; the NMDA receptor is the classic molecular example. - **Hebbian plasticity:** "cells that fire together wire together"; synapses strengthen when pre- and postsynaptic activity coincide. - **AMPA receptor:** the fast glutamate receptor that does most of the depolarizing; inserting more of them is one way a synapse gets stronger. - **LTP (long-term potentiation):** lasting strengthening of a synapse after correlated activity; the leading cellular model of learning. - **LTD (long-term depression):** lasting weakening of a synapse; also needed for learning. - **CaMKII:** calcium/calmodulin-dependent protein kinase II, an enzyme activated by Ca²⁺ entry that drives LTP. - **CREB:** a transcription factor activated in long-lasting plasticity and memory; Hou et al. 2020 report Mg²⁺ influx boosts its activation. - **p38 MAPK:** a signaling kinase; in Hou et al. 2020 it carries the Mg²⁺ signal to CREB. - **Magnesium L-threonate (MgT):** a magnesium compound developed to raise brain magnesium; tested in rats by Slutsky et al. 2010 and sold as a supplement.