Presentation
Search Abstracts | Symposia | Slide Sessions | Poster Sessions | Lightning Talks
Does the Closure Positive Shift Consist of Phase-Locked Delta-Band Oscillations?
Poster E85 in Poster Session E, Thursday, October 26, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
Lena Henke1, Burkhard Maess1, Lars Meyer1,2; 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Clinic for Phoniatrics and Pedaudiology, University Hospital Münster, Münster, Germany
The Closure Positive Shift (CPS) is an event-related brain potential associated with the termination of prosodic phrases as well as larger syntactic units, such as clauses. The likelihood of a CPS increases with the duration of the terminated unit. In addition, the CPS exhibits an endogenous period of about 2.7 seconds; that is, the occurrence of a CPS is more likely when the terminated unit is 2.7 seconds long. Recently, we and others have hypothesized that the CPS might consist of underlying neural oscillations, with increases in amplitude arising from phase-locking across trials. This is based on the observation that the phase of neural activity < 4 Hertz (i.e., delta-band oscillations) predicts the segmentation of sentences, specifically when segment duration is 2.7 seconds. To test this hypothesis, our auditory magnetoencephalography (MEG) study used sentences containing globally ambiguous relative clauses (e.g., Mrs. Groß called the nurse of the pensioner who always joked.), where the relative clause (i.e., who always joked) can be attached to either of two preceding noun phrases (i.e., NP1 the nurse or NP2 the pensioner). Prior work has found that attachment is influenced by clause duration, with long relative clauses triggering NP1-attachment. This could reflect an endogenous limit on segment duration—such as the period of delta-band oscillations. Accordingly, our design manipulated the duration of the main clause in seven levels ranging from ~2–4 seconds in order to parametrically increase the likelihood of clause termination, a CPS, and delta-band phase-locking. Preliminary results indicate that CPS amplitude increases with clause duration. Likewise, we show that the delta-band phase before the offset of the main clause correlates with clause duration. Critically, the phase of the delta band was related to the single trial CPS amplitude. In conclusion, we tentatively suggest that the CPS may reflect the time-domain equivalent of phase-locked oscillatory cycles at delta-band frequency.
Topic Areas: Speech Perception,