Priming Pictures and Words: An Investigation of the N400 and LPC

摘要: Two ERP components are discussed in relation to studies of semantic and mnemonic processing, namely the N400 LPC. The N400 is a monophasic negativity typically observed between 250 - 500 ms post-stimulus. Semantic repetition priming utilising linguistic stimuli visual modality (i.e. words, nonwords), and stimulus paradigms sentence lexical decision tasks) have indicated that readily evoked by semantic anomaly and sensitive word frequency (low words eliciting greater amplitude N400s than high words), class (larger content relatedness (larger to unrelated subject expectancy unexpected words within context), phonology non-rhyming words (attenuated following word repetition). Theoretical formulations suggest indexes the degree of spreading activation throughout network (Morton, 1969), contextual integration (Rugg, 1990), semantic expectancy (Kutas & Hillyard, 1984), or memory search process (Bentin McCarthy, 1994). Which these most accurately explains currently unresolved. Whether the negativity following anomaly paradigms employing nonlinguistic (e.g. pictures, faces, music) is reflecting same process as elicited linguistic anomaly, is also considerable debate. Enhanced LPC amplitudes language tasks recorded to final words. The broad, post positivity, occurs approximately 550-800 ms post-stimulus presumed reflect processes associated with closure (Friedman, Simson, Ritter, Rapin, 1975; Kutas 1982), certainty (Stuss, Picton, Cerri, Leech, & Stethem, 1992), integrative elaborative processing (Andrews, Mitchell, Ward, 1993). All task relevant appear elicit the LPC, its being inversely related subjective probability. The certain aspects mnemonic processing. Enhanced have been recorded stimuli which subsequently recognised, 'seen' compared to 'unseen', second presentations stimuli. Subsequent to these findings, it has hypothesised in memory reflects some associated with both encoding retrieval. Resulting from perceived similarity component various paradigms, investigators posit similar episodic processes subserve them (Besson Kutas,