FIGURE 3.

Different hypotheses about effective connectivity. (a) The dynamic causal models comprise a bilateral “input,” four “sources,” and ipsilateral “connections” among (extrinsic connections) and within (intrinsic connections) these sources. HG, Heschl's gyrus; PT, planum temporale. The four models tested had the same anatomical architecture but differed in terms of the embedding connections: intrinsic and extrinsic (forward and backward) in the full model (FM), only forward and backward in the reduced model 1 (RM1), only forward in the reduced model 2 (RM2), and no connections in the null model (NM). (b) Sources (red squares) were defined by using peak activations of the auditory oddball localizer, and are here projected onto an anatomical Montreal Neurological Institute (MNI) standard template