title: Priming within and across modalities: exploring the nature of rCBF increases and decreases.
abstract: Neuroimaging studies suggest that within-modality priming is associated with reduced regional cerebral blood flow (rCBF) in the extrastriate area, whereas cross-modality priming is associated with increased rCBF in prefrontal cortex. To characterize the nature of rCBF changes in within- and cross-modality priming, we conducted two neuroimaging experiments using positron emission tomography (PET). In experiment 1, rCBF changes in within-modality auditory priming on a word stem completion task were observed under same- and different-voice conditions. Both conditions were associated with decreased rCBF in extrastriate cortex. In the different-voice condition there were additional rCBF changes in the middle temporal gyrus and prefrontal cortex. Results suggest that the extrastriate involvement in within-modality priming is sensitive to a change in sensory modality of target stimuli between study and test, but not to a change in the feature of a stimulus within the same modality. In experiment 2, we studied cross-modality priming on a visual stem completion test after encoding under full- and divided-attention conditions. Increased rCBF in the anterior prefrontal cortex was observed in the full- but not in the divided-attention condition. Because explicit retrieval is compromised after encoding under the divided-attention condition, prefrontal involvement in cross-modality priming indicates recruitment of an aspect of explicit retrieval mechanism. The aspect of explicit retrieval that is most likely to be involved in cross-modality priming is the familiarity effect.
authors.affiliation: Department of Psychology, Harvard University, Boston, MA 02114, USA. rajendra@wjh.harvard.edu
authors.forename: R D
authors.initials: RD
authors.lastname: Badgaiyan
authors.forename: D L
authors.initials: DL
authors.lastname: Schacter
authors.forename: N M
authors.initials: NM
authors.lastname: Alpert
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology; D001519:Behavior / Q000502:physiology; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D014055:Tomography, Emission-Computed; D014796:Visual Perception / Q000502:physiology