Source
Although localization of the neural generators of an ERP signal is difficulty due to the spreading of current from the source to the sensors, multiple techniques can be used to provide converging evidence about possible neural sources. Using methods such as recordings directly off the surface of the brain or from electrodes implanted in the brain, evidence from brain damaged patients, and magnetoencephalographic (MEG) recordings (which measure magnetic activity at the scalp associated with the electrical signal measured by ERPs), the left temporal lobe has been highlighted as an important source for the N400, with additional contributions from the right temporal lobe. More generally, however, activity in a wide network of brain areas is elicited in the N400 time window, suggesting a highly distributed neural source (See Kutas & Federmeier, 2011, for a more complete discussion).
Read more about this topic: N400 (neuroscience)
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