title: Oscillatory brain activity dissociates between associative stimulus content in a repetition priming task in the human EEG.
abstract: The retrieval and formation of cortical object representations seem to require the activation of neuronal cell assemblies, correlated by synchronized neuronal activity in the gamma band range (>20 Hz). In the present electroencephalogram (EEG) study we have analysed induced gamma band activity during the repetition of familiar (meaningful) and unfamiliar (meaningless) line drawings. Results showed a broad posterior distribution of induced gamma band responses (GBRs) after the initial presentation of a familiar stimulus. Repeated presentations of the same picture resulted in a decrease of GBRs, accompanied by a decrease in the number of electrode pairs exhibiting significant phase-locking values. These effects might be linked to a 'sharpening' mechanism within a cell assembly representing a familiar object. In contrast, the re-presentation of primed unfamiliar stimuli was associated with an augmentation of gamma power and an increase in significantly phase-locked pairs of electrodes. These findings might be a signature of the formation of a new cortical network representing an object. Event related potentials (ERPs) showed a decrease in amplitude independent of the stimuli's associative content, and, thus, seem to play a complementary role in repetition priming as compared to high-frequency brain dynamics.
authors.affiliation: Institut für Allgemeine Psychologie, Universität Leipzig, Leipzig, Germany. gruber@rz.uni-leipzig.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Gruber
authors.forename: Matthias M
authors.initials: MM
authors.lastname: Müller
mesh_terms: D000328:Adult; D001245:Association Learning / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology; D010507:Periodicity