MEG recordings from adults during the semantic priming task developed for infants. (A) Averaged single channel event-related fields from a representative adult during the semantic priming task shown in . A sustained differential response (incongruous > congruous) is observed at a similar latency (350–550 ms) as infants, but the peak of the differential response may occur earlier for adults. This differential response is significant across trials for the 200-ms time window (350–550 ms) (P < 0.00001 [purple channel]; with a trend in the [blue channel] P < 0.08). Two-way t-test, P < 0.05, degrees of freedom = 98. (B) Whole-head MEG sensor array recordings of the semantic priming response in the same adult. Color coding indicates the left temporal gradiometer channels that correspond to where differential word selective, semantic, and repetition priming responses were observed in infants (, Supplementary Fig. S2). (C) Center: Adult average dSPM (n = 7) to incongruous minus congruous words at the same latency (500–550 ms) as the infant group response () displayed on the cortical surface (dark gray = sulci, light gray = gyri). Similar to infants, sources generating the differential semantic priming response are estimated in adults to left posterior prefrontal, perisylvian, and anterolateral temporal regions, with weaker activation in homologous right hemisphere sites. Color indicates signal-to-noise relative to prestimulus baseline (full red at sqrtF = 1.7 corresponding to P < 10−2, full yellow at sqrtF = 3.5, P < 10−12). Surround: Average time courses for the estimated noise-normalized dipole strength to incongruous (red) and congruous (blue) words in the same 6 bilateral ROIs used for infant analyses. The amplitude of the time course to congruent and incongruent words from 500 to 550 ms was determined in each adult subject and compared with a paired t-test. Time courses with a * indicate regions where a significant difference was found (# = trend). IFS, inferior frontal sulcus; STS, superior temporal sulcus; ITS, inferior temporal sulcus.