Fig. 4.

Time courses of auditory cortex signals and lateralized motor signals. In all plots, the shaded area represents the time window during which the amplitude of the signal in left auditory cortex is significantly higher in compatible vs. incompatible trials (the cluster extent in time in the nonparametric randomization tests, see results; the shading in A and B corresponds to the same time windows as in Fig. 3, B and C, respectively). The solid and dotted horizontal bars represent the mean (±SD) RT in the compatible and incompatible condition, respectively. The diamond in A and B, top, represents the mean expected latency of the auditory M100 (∼100 ms after stimulus onset). Solid line, compatible trials; dotted line, incompatible trials. All time courses are smoothed with a square kernel of 20 ms for visualization. A, top: time courses of prime-locked signals in left auditory cortex; bottom, lateralized motor cortical signals [pressed left minus pressed right, left- vs. right-hemispheric motor hand area; c.f., lateralized readiness potential (Praamstra et al. 1999)]. In the results, we describe motor lateralization with respect to two successive time windows, marked here by I and II. B: same as A, but after matching compatible and incompatible trials for RT. The prime-target compatibility effect (A, top and B, top) emerges at a time when the specification of the motor command is ongoing, as indexed by a dominant influence of the prime on motor lateralization (A, bottom and B, bottom, I and II.). a.u., Arbitrary units.