Markus Kiefer

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The cortical organization of executive control was investigated using event-related potentials (ERPs). ERPs were collected while subjects performed a go/no go task that required response inhibition. First, around 260 ms after stimulus onset, an effect of response inhibition on ERPs was observed over inferior prefrontal areas. Generators in these regions(More)
It is a matter of debate whether the N400 component of the event-related brain potential (ERP) is sensitive to unconscious automatic priming mechanisms or to strategic mechanisms only. Recent studies demonstrated N400 modulation by masked primes at a short SOA supporting an automatic spreading activation account. However, it cannot be ruled out that(More)
Conceptual representations in long-term memory crucially contribute to perception and action, language and thought. However, the precise nature of these conceptual memory traces is discussed controversially. In particular, the grounding of concepts in the sensory and motor brain systems is the focus of a current debate. Here, we review theoretical accounts(More)
A robust finding in the cross-cultural research is that people's memories for faces of their own race are superior to their memories for other-race faces. However, the mechanisms underlying the own-race effect have not been well defined. In this study, a holistic explanation was examined in which Caucasian and Asian participants were asked to recognize(More)
In two experiments the effect of object category on event-related potentials (ERPs) was assessed while subjects performed superordinate categorizations with pictures and words referring to objects from natural (e.g., animal) and artifactual (e.g., tool) categories. First, a category probe was shown that was presented as name in Experiment 1 and as picture(More)
Traditionally, concepts are conceived as abstract mental entities distinct from perceptual or motor brain systems. However, recent results let assume modality-specific representations of concepts. The ultimate test for grounding concepts in perception requires the fulfillment of the following four markers: conceptual processing during (1) an implicit task(More)
Event-related brain potentials (ERPs) were used to investigate the neurophysiological correlates of conscious and unconscious semantic processing. Masked words, which do not enter consciousness, as well as visible words, were shown to modulate the N400 ERP potential to subsequently presented, meaningfully related target words. The N400 is known as an(More)
Emotions have been shown to modulate memory processes. However, the neuronal substrate underlying these modulatory effects is largely unknown. Using event-related functional magnetic resonance imaging (fMRI), we investigated whether the context of emotional encoding modulates brain activation predictive for subsequent recall of emotionally neutral material.(More)
It has been controversially discussed whether the error-related negativity (ERN) or error negativity (N(e)), an electrophysiological index of anterior cingulate activation, reflects response conflict or response evaluation subserving error monitoring processes. We investigated event-related potentials (ERPs) in a guessing task which did not induce response(More)
Physical activity and aerobic exercise in particular, promotes health and effective cognitive functioning. To elucidate mechanisms underlying the beneficial effects of physical fitness and acute exercise, behavioral and electrophysiological indices of task preparation and response inhibition as a part of executive functions were assessed in a modified(More)