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Electrophysiological activation by masked primes: Independence of prime-related and target-related activities.

Klotz W, Heumann M, Ansorge U, Neumann O - Adv Cogn Psychol (2008)

Bottom Line: Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP.Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding.The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Bielefeld, Bielefeld, Germany.

ABSTRACT
Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP. Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding. To analyze the electrophysiological responses, we computed the LRP and applied an averaging method separating the activation due to the prime and the target. The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

No MeSH data available.


Upper panel: Grand average LRP waveforms of Experiment 1. Depicted								are Nogo (masked), congruent, and incongruent conditions. Data were								smoothed for this and all other figures, using floating means over								17 samples. The smoothing of the data concerns only the figures, not								the statistical analyses. Lower panel: Grand average waveforms of								the calculated LRP effects across conditions of prime and target in								Experiment 1. Symbols stand for LRP onsets.
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Figure 2: Upper panel: Grand average LRP waveforms of Experiment 1. Depicted are Nogo (masked), congruent, and incongruent conditions. Data were smoothed for this and all other figures, using floating means over 17 samples. The smoothing of the data concerns only the figures, not the statistical analyses. Lower panel: Grand average waveforms of the calculated LRP effects across conditions of prime and target in Experiment 1. Symbols stand for LRP onsets.

Mentions: Out of all trials, 20% had to be excluded because of artifacts. Discarded trials were equally distributed across conditions. Figure 2 (upper panel) shows the grand average LRPs for the three conditions. The onsets of the waveforms obtained in congruent and incongruent trials qualitatively mimic the pattern of the RT data: The onset of the congruent waveform is at 232 ms, the onset of the incongruent waveform at 292 ms. The LRP of the nogo trials also deviated from baseline, starting at 224 ms.


Electrophysiological activation by masked primes: Independence of prime-related and target-related activities.

Klotz W, Heumann M, Ansorge U, Neumann O - Adv Cogn Psychol (2008)

Upper panel: Grand average LRP waveforms of Experiment 1. Depicted								are Nogo (masked), congruent, and incongruent conditions. Data were								smoothed for this and all other figures, using floating means over								17 samples. The smoothing of the data concerns only the figures, not								the statistical analyses. Lower panel: Grand average waveforms of								the calculated LRP effects across conditions of prime and target in								Experiment 1. Symbols stand for LRP onsets.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864997&req=5

Figure 2: Upper panel: Grand average LRP waveforms of Experiment 1. Depicted are Nogo (masked), congruent, and incongruent conditions. Data were smoothed for this and all other figures, using floating means over 17 samples. The smoothing of the data concerns only the figures, not the statistical analyses. Lower panel: Grand average waveforms of the calculated LRP effects across conditions of prime and target in Experiment 1. Symbols stand for LRP onsets.
Mentions: Out of all trials, 20% had to be excluded because of artifacts. Discarded trials were equally distributed across conditions. Figure 2 (upper panel) shows the grand average LRPs for the three conditions. The onsets of the waveforms obtained in congruent and incongruent trials qualitatively mimic the pattern of the RT data: The onset of the congruent waveform is at 232 ms, the onset of the incongruent waveform at 292 ms. The LRP of the nogo trials also deviated from baseline, starting at 224 ms.

Bottom Line: Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP.Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding.The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Bielefeld, Bielefeld, Germany.

ABSTRACT
Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP. Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding. To analyze the electrophysiological responses, we computed the LRP and applied an averaging method separating the activation due to the prime and the target. The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

No MeSH data available.