Cerebral Strategies in the Segmentation and Interpretation of Speech

The segmentation of the acoustic speech signal is a fundamental for the processing of spoken language. The paper at hand provides a survey of studies conducted in our lab concerning the detection of segmentation cues in the speech signal and associated perception of prosodic boundaries. The first two studies presented here employ the methodology of Event-Related Potentials (ERP) to study online electrophysiological responses to acoustic stimuli varying in syntactic and prosodic constituency, as well as in segmental content. By the first study an ERP shift was identified correlated with the perception of major intonational boundaries which was termed the Closure Positive Shift (CPS). The second study was especially concerned with listener‘s abilities in speech segmentation, given the exclusive presence of prosodic cues. A third experiment reviewed here employs functional Magnetic Resonance Imaging (fMRI), an investigation method based on hemodynamic brain responses. ERP and fMRI are complementary methodologies: while ERPs provide an accurate measure of temporal aspects of processing, fMRI methodology is particularly well suited to localize such processes in the brain.