The cortical organization of speech processing: feedback control and predictive coding the context of a dual-stream model.

Speech recognition is an active process that involves some form of predictive coding. This statement is relatively uncontroversial. What is less clear is the source of the prediction. The dual-stream model of speech processing suggests that there are two possible sources of predictive coding in speech perception: the motor speech system and the lexical-conceptual system. Here I provide an overview of the dual-stream model of speech processing and then discuss evidence concerning the source of predictive coding during speech recognition. I conclude that, in contrast to recent theoretical trends, the dorsal sensory-motor stream is not a source of forward prediction that can facilitate speech recognition. Rather, it is forward prediction coming out of the ventral stream that serves this function.