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The N400 and Late Positive Complex (LPC) Effects Reflect Controlled Rather than Automatic Mechanisms of Sentence Processing.

Daltrozzo J, Wioland N, Kotchoubey B - Brain Sci (2012)

Bottom Line: Under mild degradation, where controlled sentence-level processing could still occur (as indicated by behavioral data), both N400 and LPC effects were delayed and the latter effect was reduced.These results suggest that ERP effects elicited in complex contexts, such as sentences, reflect controlled rather than automatic mechanisms of speech processing.These results differ from the results of experiments that used word-pair or word-list paradigms.

View Article: PubMed Central - PubMed

Affiliation: CNRS UMR7237, Louis Pasteur University, 12 rue Goethe, Strasbourg F-67000, France. jdaltrozzo@olfac.univ-lyon1.fr.

ABSTRACT
This study compared automatic and controlled cognitive processes that underlie event-related potentials (ERPs) effects during speech perception. Sentences were presented to French native speakers, and the final word could be congruent or incongruent, and presented at one of four levels of degradation (using a modulation with pink noise): no degradation, mild degradation (2 levels), or strong degradation. We assumed that degradation impairs controlled more than automatic processes. The N400 and Late Positive Complex (LPC) effects were defined as the differences between the corresponding wave amplitudes to incongruent words minus congruent words. Under mild degradation, where controlled sentence-level processing could still occur (as indicated by behavioral data), both N400 and LPC effects were delayed and the latter effect was reduced. Under strong degradation, where sentence processing was rather automatic (as indicated by behavioral data), no ERP effect remained. These results suggest that ERP effects elicited in complex contexts, such as sentences, reflect controlled rather than automatic mechanisms of speech processing. These results differ from the results of experiments that used word-pair or word-list paradigms.

No MeSH data available.


Grand averaged subtraction waveforms between ERP to incongruent targets and ERP to congruent targets at each degradation level (no degradation: DL0; “low” degradation: DL1; “medium” degradation: DL2; “strong” degradation: DL3) (N = 20 participants, vertical unit: µV with negativity upward, horizontal unit: ms).
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brainsci-02-00267-f004: Grand averaged subtraction waveforms between ERP to incongruent targets and ERP to congruent targets at each degradation level (no degradation: DL0; “low” degradation: DL1; “medium” degradation: DL2; “strong” degradation: DL3) (N = 20 participants, vertical unit: µV with negativity upward, horizontal unit: ms).

Mentions: A second analysis was performed with an a priori choice of time intervals of the N400 effect and LPC effect across DLs based on the grand-averaged ERPs (Figure 3 and Figure 4). Repeated-measures ANOVA with Tukey post hoc tests were performed for each DL and for each ERP effect with an a priori time window using the same factors as in the previous analysis except that the DL factor was not included.


The N400 and Late Positive Complex (LPC) Effects Reflect Controlled Rather than Automatic Mechanisms of Sentence Processing.

Daltrozzo J, Wioland N, Kotchoubey B - Brain Sci (2012)

Grand averaged subtraction waveforms between ERP to incongruent targets and ERP to congruent targets at each degradation level (no degradation: DL0; “low” degradation: DL1; “medium” degradation: DL2; “strong” degradation: DL3) (N = 20 participants, vertical unit: µV with negativity upward, horizontal unit: ms).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061799&req=5

brainsci-02-00267-f004: Grand averaged subtraction waveforms between ERP to incongruent targets and ERP to congruent targets at each degradation level (no degradation: DL0; “low” degradation: DL1; “medium” degradation: DL2; “strong” degradation: DL3) (N = 20 participants, vertical unit: µV with negativity upward, horizontal unit: ms).
Mentions: A second analysis was performed with an a priori choice of time intervals of the N400 effect and LPC effect across DLs based on the grand-averaged ERPs (Figure 3 and Figure 4). Repeated-measures ANOVA with Tukey post hoc tests were performed for each DL and for each ERP effect with an a priori time window using the same factors as in the previous analysis except that the DL factor was not included.

Bottom Line: Under mild degradation, where controlled sentence-level processing could still occur (as indicated by behavioral data), both N400 and LPC effects were delayed and the latter effect was reduced.These results suggest that ERP effects elicited in complex contexts, such as sentences, reflect controlled rather than automatic mechanisms of speech processing.These results differ from the results of experiments that used word-pair or word-list paradigms.

View Article: PubMed Central - PubMed

Affiliation: CNRS UMR7237, Louis Pasteur University, 12 rue Goethe, Strasbourg F-67000, France. jdaltrozzo@olfac.univ-lyon1.fr.

ABSTRACT
This study compared automatic and controlled cognitive processes that underlie event-related potentials (ERPs) effects during speech perception. Sentences were presented to French native speakers, and the final word could be congruent or incongruent, and presented at one of four levels of degradation (using a modulation with pink noise): no degradation, mild degradation (2 levels), or strong degradation. We assumed that degradation impairs controlled more than automatic processes. The N400 and Late Positive Complex (LPC) effects were defined as the differences between the corresponding wave amplitudes to incongruent words minus congruent words. Under mild degradation, where controlled sentence-level processing could still occur (as indicated by behavioral data), both N400 and LPC effects were delayed and the latter effect was reduced. Under strong degradation, where sentence processing was rather automatic (as indicated by behavioral data), no ERP effect remained. These results suggest that ERP effects elicited in complex contexts, such as sentences, reflect controlled rather than automatic mechanisms of speech processing. These results differ from the results of experiments that used word-pair or word-list paradigms.

No MeSH data available.