Apart from measuring the electric field around the skull it is possible to measure the magnetic field directly in a technique known asmagnetoencephalography (MEG). This technique has the same temporal resolution as EEG but much better spatial resolution, although not as good as Magnetic Resonance Imaging (MRI). The greatest disadvantage of MEG is that, because the magnetic fields generated by neural activity are very weak, the method is only capable of picking up signals from near the surface of the cortex, and even then, only neurons located in the depths of cortical folds (sulci) have dendrites oriented in a way that gives rise to detectable magnetic fields outside the skull.