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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.


Related in: MedlinePlus

Waveforms and spectrograms of three sentences on the left (Si tu vas jouer dehors, n’oublie pas ton manteau.), middle (Ils ont visité la France pendant les vacances.), and right panel (La maîtresse a recopié l’exercice sur le tableau.) in the four degradation conditions. The bottom panel shows the no degradation condition (DL0), the second panel from the bottom shows the “low” degradation condition (DL1), the second panel from the top shows the “medium” degradation condition (DL2), and the top panel shows the “strong” degradation condition (DL3). Waveforms vertical scale range from 0 to −∞ (Unit: dB). Spectrogram vertical scale range from 0 kHz to 5 kHz (linear scale). Waveform and spectrogram horizontal time axis range from 0 s to the sentence duration, i.e., 2.08 s for the left panel, 2.57 s for the middle panel, and 2.70 s for the right panel.
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brainsci-02-00267-f001: Waveforms and spectrograms of three sentences on the left (Si tu vas jouer dehors, n’oublie pas ton manteau.), middle (Ils ont visité la France pendant les vacances.), and right panel (La maîtresse a recopié l’exercice sur le tableau.) in the four degradation conditions. The bottom panel shows the no degradation condition (DL0), the second panel from the bottom shows the “low” degradation condition (DL1), the second panel from the top shows the “medium” degradation condition (DL2), and the top panel shows the “strong” degradation condition (DL3). Waveforms vertical scale range from 0 to −∞ (Unit: dB). Spectrogram vertical scale range from 0 kHz to 5 kHz (linear scale). Waveform and spectrogram horizontal time axis range from 0 s to the sentence duration, i.e., 2.08 s for the left panel, 2.57 s for the middle panel, and 2.70 s for the right panel.

Mentions: Four degradation levels (DLs) were used: no degradation (DL0), “low” degradation (DL1), “medium” degradation (DL2) and “strong” degradation (DL3). DL3 was obtained by: (1) a modulation of the sentences acoustic signal with a pink noise (intensity: −10.8 dB generated and measured by Adobe Audition 1.5) and (2) an amplification of the degraded signal (according to the root mean squared overall intensity computed by Adobe Audition 1.5). The resulting signal to noise ratio ranged from −2.85 to 0.08 dB (as measured by Adobe Audition 1.5). DL2 and DL1 were obtained with the same procedure except that before modulation, the pink noise was low-pass filtered using a fast Fourier transformation (with Adobe Audition 1.5) at 4000 Hz and 2000 Hz, respectively. This procedure resulted in filtered pink noise of −11.4 dB and −11.8 dB, respectively, and after modulation, resulted in a signal to noise ratio ranging from −3.09 to −0.16 dB for DL2 and from −3.24 to −0.30 dB for DL1 (see Figure 1).


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)

Waveforms and spectrograms of three sentences on the left (Si tu vas jouer dehors, n’oublie pas ton manteau.), middle (Ils ont visité la France pendant les vacances.), and right panel (La maîtresse a recopié l’exercice sur le tableau.) in the four degradation conditions. The bottom panel shows the no degradation condition (DL0), the second panel from the bottom shows the “low” degradation condition (DL1), the second panel from the top shows the “medium” degradation condition (DL2), and the top panel shows the “strong” degradation condition (DL3). Waveforms vertical scale range from 0 to −∞ (Unit: dB). Spectrogram vertical scale range from 0 kHz to 5 kHz (linear scale). Waveform and spectrogram horizontal time axis range from 0 s to the sentence duration, i.e., 2.08 s for the left panel, 2.57 s for the middle panel, and 2.70 s for the right panel.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

brainsci-02-00267-f001: Waveforms and spectrograms of three sentences on the left (Si tu vas jouer dehors, n’oublie pas ton manteau.), middle (Ils ont visité la France pendant les vacances.), and right panel (La maîtresse a recopié l’exercice sur le tableau.) in the four degradation conditions. The bottom panel shows the no degradation condition (DL0), the second panel from the bottom shows the “low” degradation condition (DL1), the second panel from the top shows the “medium” degradation condition (DL2), and the top panel shows the “strong” degradation condition (DL3). Waveforms vertical scale range from 0 to −∞ (Unit: dB). Spectrogram vertical scale range from 0 kHz to 5 kHz (linear scale). Waveform and spectrogram horizontal time axis range from 0 s to the sentence duration, i.e., 2.08 s for the left panel, 2.57 s for the middle panel, and 2.70 s for the right panel.
Mentions: Four degradation levels (DLs) were used: no degradation (DL0), “low” degradation (DL1), “medium” degradation (DL2) and “strong” degradation (DL3). DL3 was obtained by: (1) a modulation of the sentences acoustic signal with a pink noise (intensity: −10.8 dB generated and measured by Adobe Audition 1.5) and (2) an amplification of the degraded signal (according to the root mean squared overall intensity computed by Adobe Audition 1.5). The resulting signal to noise ratio ranged from −2.85 to 0.08 dB (as measured by Adobe Audition 1.5). DL2 and DL1 were obtained with the same procedure except that before modulation, the pink noise was low-pass filtered using a fast Fourier transformation (with Adobe Audition 1.5) at 4000 Hz and 2000 Hz, respectively. This procedure resulted in filtered pink noise of −11.4 dB and −11.8 dB, respectively, and after modulation, resulted in a signal to noise ratio ranging from −3.09 to −0.16 dB for DL2 and from −3.24 to −0.30 dB for DL1 (see Figure 1).

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.


Related in: MedlinePlus