Separating the visual sentence N400 effect from the P400 sequential expectancy effect: cognitive and neuroanatomical implications.

The N400 is an event-related potential (ERP) component that is elicited by semantically meaningful stimuli; one of its defining characteristics is that it is amplified for sentence completions that are semantically unexpected or incongruous with the preceding context. Some prior reports using visual sentence reading paradigms have suggested that there may also be a Cz-centered P400 (a P400cz) that is also responding to semantic congruity manipulations, distinct from the classic Pz-centered N400 (the N400pz). In the present experiment, sentences were presented visually one word at a time, and half of the sentences ended with a semantically incongruent ending.

fMRI characterization of the language formulation area.

Participants read sentences presented one word at a time, half of which ended with a semantically incongruent ending. 1.5T functional magnetic resonance imaging data were collected from 11 participants, showing that the left posterior inferior temporal region, which has previously been termed the Language Formulation Area (LFA), responded to cloze probability.