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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 2. Depicted are								congruent, neutral, and incongruent conditions. Middle panel: Grand average								waveforms of the calculated LRP effects across conditions of prime and								target in Experiment 2. Lower panel: Directly measured congruent and								incongruent conditions in comparison to the calculated congruent and								incongruent conditions. The basis for the calculated conditions is the								neutral condition. Calculated congruent and incongruent conditions result								from the directly measured neutral prime activity plus/minus the prime								activity averaged across congruent and incongruent conditions. Symbols stand								for LRP onsets.
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Figure 3: Upper panel: Grand average LRP waveforms of Experiment 2. Depicted are congruent, neutral, and incongruent conditions. Middle panel: Grand average waveforms of the calculated LRP effects across conditions of prime and target in Experiment 2. Lower panel: Directly measured congruent and incongruent conditions in comparison to the calculated congruent and incongruent conditions. The basis for the calculated conditions is the neutral condition. Calculated congruent and incongruent conditions result from the directly measured neutral prime activity plus/minus the prime activity averaged across congruent and incongruent conditions. Symbols stand for LRP onsets.

Mentions: Besides the effects on RT and error rate, other studies with this method (e.g., Eimer, 1999; Jaśkowski, van der Lubbe, Schlotterbeck, & Verleger, 2002; Schlaghecken & Eimer, 2001) or similar paradigms (Leuthold & Kopp, 1998; Vath & Schmidt, 2007) have shown that the primes also exert a significant effect on the lateralized readiness potential (LRP). The LRP (for an overview, see Eimer, 1998) is a lateralized negativity that can be recorded from the scalp over the motor cortices prior to response execution. It is stronger over the motor cortex contralateral to the responding hand, and hence, the difference potential between the left and right hemispheres can be used as a measure of the selective preparation of a right or left hand response. The authors of the cited studies were able to show that the incongruent prime not only delayed the onset of the LRP, but that the incongruent LRP also deflected (“dipped”) in the direction of the primed response (e.g., see Figure 3, upper panel). This indicates that initially, a response is prepared that corresponds to the position of the target-similar shaped prime, even if the location of the target then ultimately demands the opposite response (see Jaśkowski et al., 2002, who discern motor from attentional lateralization).


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 2. Depicted are								congruent, neutral, and incongruent conditions. Middle panel: Grand average								waveforms of the calculated LRP effects across conditions of prime and								target in Experiment 2. Lower panel: Directly measured congruent and								incongruent conditions in comparison to the calculated congruent and								incongruent conditions. The basis for the calculated conditions is the								neutral condition. Calculated congruent and incongruent conditions result								from the directly measured neutral prime activity plus/minus the prime								activity averaged across congruent and incongruent conditions. Symbols stand								for LRP onsets.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Upper panel: Grand average LRP waveforms of Experiment 2. Depicted are congruent, neutral, and incongruent conditions. Middle panel: Grand average waveforms of the calculated LRP effects across conditions of prime and target in Experiment 2. Lower panel: Directly measured congruent and incongruent conditions in comparison to the calculated congruent and incongruent conditions. The basis for the calculated conditions is the neutral condition. Calculated congruent and incongruent conditions result from the directly measured neutral prime activity plus/minus the prime activity averaged across congruent and incongruent conditions. Symbols stand for LRP onsets.
Mentions: Besides the effects on RT and error rate, other studies with this method (e.g., Eimer, 1999; Jaśkowski, van der Lubbe, Schlotterbeck, & Verleger, 2002; Schlaghecken & Eimer, 2001) or similar paradigms (Leuthold & Kopp, 1998; Vath & Schmidt, 2007) have shown that the primes also exert a significant effect on the lateralized readiness potential (LRP). The LRP (for an overview, see Eimer, 1998) is a lateralized negativity that can be recorded from the scalp over the motor cortices prior to response execution. It is stronger over the motor cortex contralateral to the responding hand, and hence, the difference potential between the left and right hemispheres can be used as a measure of the selective preparation of a right or left hand response. The authors of the cited studies were able to show that the incongruent prime not only delayed the onset of the LRP, but that the incongruent LRP also deflected (“dipped”) in the direction of the primed response (e.g., see Figure 3, upper panel). This indicates that initially, a response is prepared that corresponds to the position of the target-similar shaped prime, even if the location of the target then ultimately demands the opposite response (see Jaśkowski et al., 2002, who discern motor from attentional lateralization).

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.