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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.


Sequence of stimulus presentation.
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brainsci-02-00267-f002: Sequence of stimulus presentation.

Mentions: For the primary (ERP) study, behavioral data were recorded with a recognition task. To record performance data, to control the level of attention to the final word of the auditory sentence (i.e., the “ERP target word”), and to check that the sentences were semantically processed, a visual (“recognition target”) word was presented after each auditory sentence with an inter-stimulus interval of 1.5 s (i.e., after the ERPs to the ERP target had been recorded, see Figure 2). The visual word was, on average, 10 cm long and 1.5 cm high and was presented at a distance of about 70 cm (with a vertical viewing angle of 1.2° and a mean horizontal angle of 8.1°). The visual word was displayed in white lower case on a dark background in the center of a 13-inch computer screen. Participants were asked to fixate the center of the screen where the probe was displayed during the whole test.


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)

Sequence of stimulus presentation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

brainsci-02-00267-f002: Sequence of stimulus presentation.
Mentions: For the primary (ERP) study, behavioral data were recorded with a recognition task. To record performance data, to control the level of attention to the final word of the auditory sentence (i.e., the “ERP target word”), and to check that the sentences were semantically processed, a visual (“recognition target”) word was presented after each auditory sentence with an inter-stimulus interval of 1.5 s (i.e., after the ERPs to the ERP target had been recorded, see Figure 2). The visual word was, on average, 10 cm long and 1.5 cm high and was presented at a distance of about 70 cm (with a vertical viewing angle of 1.2° and a mean horizontal angle of 8.1°). The visual word was displayed in white lower case on a dark background in the center of a 13-inch computer screen. Participants were asked to fixate the center of the screen where the probe was displayed during the whole test.

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.