Sentential influences on acoustic-phonetic processing: A Granger causality analysis of multimodal imaging data.
Sentential context influences the way that listeners identify phonetically ambiguous or perceptual degraded speech sounds. Unfortunately, inherent inferential limitations on the interpretation of behavioral or BOLD imaging results make it unclear whether context influences perceptual processing directly, or acts at a post-perceptual decision stage. In this paper, we use Kalman-filter enabled Granger causation analysis of MR-constrained MEG/EEG data to distinguish between these possibilities. Using a retrospective probe verification task, we found that sentential context strongly affected the interpretation of words with ambiguous initial voicing (e.g. DUSK-TUSK). This behavioral context effect coincided with increased influence by brain regions associated with lexical representation on regions associated with acoustic-phonetic processing. These results support an interactive view of sentence context effects on speech perception.
Neuropsychology Laboratory, Massachusetts General Hospital, 175 Cambridge St., CPZ S340, Boston, MA 02114; Department of Psychology, Salem State University, 352 Lafayette St., Salem, MA 01970; Athinoula A. Martinos Center for Biomedical Imaging. Massachusetts General Hospital, 149 Thirteenth St., S2301, Charlestown, MA.02129; Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Ave., E25-519, Cambridge, MA 02139.
David W
DW
Gow
Neuropsychology Laboratory, Massachusetts General Hospital, 175 Cambridge St., CPZ S340, Boston, MA 02114; Athinoula A. Martinos Center for Biomedical Imaging. Massachusetts General Hospital, 149 Thirteenth St., S2301, Charlestown, MA.02129.
Bruna B
BB
Olson
modularity; semantic context effect; sentential context effect; speech perception; top-down processing