On the origin of the N400 effects: An ERP waveform and source localization analysis in three matching tasks

Asaid Khateb, Alan J. Pegna, Theodor Landis, Michaël S. Mouthon, Jean Marie Annoni

Research output: Contribution to journalArticlepeer-review


The question of the cognitive nature and the cerebral origins of the event-related potential (ERP) N400 component has frequently been debated. Here, the N400 effects were analyzed in three tasks. In the semantic task, subjects decided whether sequentially presented word pairs were semantically related or unrelated. In the phonologic (rhyme detection) task, they decided if words were phonologically related or not. In the image categorization task, they decided whether images were categorically related or not. Difference waves between ERPs to unrelated and related conditions (defined here as the N400 effect) demonstrated a greater amplitude and an earlier peak latency effect in the image than in semantic and phonologic tasks. In contrast, spatial correlation analysis revealed that the maps computed during the peak of the N400 effects were highly correlated. Source localization computed from these maps showed the involvement in all tasks of the middle/superior temporal gyrus. Our results suggest that these qualitatively similar N400 effects index the same cognitive content despite differences in the representational formats (words vs. images) and the types of mismatch (semantic vs. phonological) across tasks.

Original languageEnglish
Pages (from-to)311-320
Number of pages10
JournalBrain Topography
Issue number3
StatePublished - Sep 2010

Bibliographical note

Funding Information:
Acknowledgments This research was supported by the Swiss National Science Foundation grants no’ 325100-118362 and 320030-125196, and the EEG Brain Mapping Core of the Center for Biomedical Imaging (CIBM) of Geneva and Lausanne. We thank Drs Rolando Grave de Peralta Menedez and Sara Gonzales Andino for the inverse solutions, and Tatiana Aboulafia for her contribution to the analysis of part of the data.


  • Event-related potentials
  • Image categorization
  • Rhyme detection
  • Semantic judgment
  • Source localization

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Anatomy


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