NMDA receptor. NMDA receptors (NMDAR), glutamate receptors are the predominant molecular device for synaptic plasticity and to control the memory function.
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Electromagnets usually consist of a large number of closely spaced turns of wire that create the magnetic field.
1 A magnet creates an invisible area of magnetism all around it called a magnetic field.  The north pole of a magnet points roughly toward Earth's north pole and vice-versa. That's because Earth itself contains magnetic materials and behaves like a gigantic magnet.