title: The effect of repetition lag on electrophysiological and haemodynamic correlates of visual object priming.
abstract: The modulation of repetition effects by the lag between first and second presentations of a visual object during a speeded semantic judgment task was examined using both scalp event-related potentials (ERPs) and event-related functional magnetic resonance imaging (efMRI). Four levels of lag were used within a single session, from zero to one, to tens of intervening stimuli, and which allowed partial separation of the effects of interference from the effects of time. Reaction times (RTs) showed that the magnitude of repetition priming decreased as lag increased. The ERP data showed two distinct effects of repetition, one between 150 and 300 ms post stimulus and another between 400 and 600 ms. The magnitude of both effects, particularly the earlier one, decreased as lag increased. The fMRI data showed a decrease in the haemodynamic response associated with repetition in several inferior occipitotemporal regions, the magnitude of which also typically decreased as lag increased. In general, and contrary to expectations, lag appeared to have mainly quantitative effects on the three types of dependent variable: there was little evidence for qualitative differences in the neural correlates of repetition effects at different lags.
authors.affiliation: Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, London, UK. r.henson@ucl.ac.uk
authors.forename: R N
authors.initials: RN
authors.lastname: Henson
authors.forename: A
authors.initials: A
authors.lastname: Rylands
authors.forename: E
authors.initials: E
authors.lastname: Ross
authors.forename: P
authors.initials: P
authors.lastname: Vuilleumeir
authors.forename: M D
authors.initials: MD
authors.lastname: Rugg
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009778:Occipital Lobe / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011601:Psychophysics; D011930:Reaction Time / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D012858:Size Perception / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology
chemical_list: D010100:Oxygen