The combination of intrinsic (spin-transfer torque) and extrinsic (resistive switching) mechanisms naturally leads to a second-order memristive system described by the state vector x = (x 1, x 2), where x 1 describes the magnetic state of the electrodes and x 2 denotes the resistive state of the MgO barrier. In this case the change of x 1 is current-controlled (spin torque is due to a high current density) whereas the change of x 2 is voltage-controlled (the drift of oxygen vacancies is due to high electric fields). The presence of both effects in a memristive magnetic tunnel junction led to the idea of a nanoscopic synapse-neuron system.