Predictive Brain Activity Shows Congruent Semantic Speci fi city in Language Comprehension and Production

Sentence fragments strongly predicting a speci fi c subsequent meaningful word elicit larger preword slow waves, prediction potentials (PPs), than unpredictive contexts. To test the current predictive processing models, 128 -channel EEG data were collected from both sexes to examine whether (1) different semantic PPs are elicited in language comprehension and production and (2) whether these PPs originate from the same speci fi c " prediction area(s) " or rather from widely distributed category -speci fi c neuronal circuits re fl ecting the meaning of the predicted item. Slow waves larger after predictable than unpredictable contexts were present both before subjects heard the sentence - fi nal word in the comprehension experiment and before they pronounced the sentence - fi nal word in the production experiment. Crucially, cortical sources underlying the semantic PP were distributed across several cortical areas and differed between the semantic categories of the expected words. In both production and comprehension, the anticipation of animal words was re fl ected by sources in posterior visual areas, whereas predictable tool words were preceded by sources in the frontocentral sensorimotor cortex. For both modalities, PP size increased with higher cloze probability, thus further con fi rming that it re fl ects semantic prediction, and with shorter latencies with which participants completed sentence fragments. These results sit well with theories viewing distributed semantic category -speci fi c circuits as the mechanistic basis of semantic prediction in the two modalities.