Presentation on theme: "Priming, Implicit Memory, and the Brain:"— Presentation transcript:
1 Priming, Implicit Memory, and the Brain: A Neuroimaging PerspectiveDaniel L. SchacterHarvard University
2 Acknowledgements Memory Lab, Harvard Psychology Donna AddisElissa AminoffElizabeth ChuaRachel Garoff-EatonAngela GutchessDale StevensGagan WigAlana WongAthinoula A. Martinos Center for Biomedical ImagingSupported by NIMH and NIA
13 Picture Fragment ID after 17 Years (M Age = 39.2; Mitchell, 2006)
14 *Unaffected or even reduced by semantic or elaborative Some Properties of Priming on Stem Completion,Fragment Completion and Identification Tests*Unaffected or even reduced by semantic or elaborativeencoding manipulations that enhance recall and recognition.*Sensitive to changes between study and test in the physicalfeatures of target items: sensory modality, word font, case.Such changes typically have smaller effects on recall andrecognition.*Typically preserved in amnesic patients with impairmentson recall and reocgnition tests.
15 Characterizing Dissociations: Memory Systems Priming on tests such as completion and identificationis little affected by semantic processing and highlydependent on physical features of stimuli.Led to postulation of perceptual representation system(‘PRS’): involves storage/retrieval of modality-specific information that supports identification ofwords/objects (Schacter, 1990;Tulving & Schacter, 1990).“Pre-semantic” collection of susbsystems (visualword form, auditory word form, structural description)that depend on posterior cortical brain regions, nothippocampus/MTL; should be preserved in amnesia.
19 Specificity of Priming-Related Reductions Neural correlates of priming for:Novel objectsRepeated same objectsRepeated different objects18 subjects scanned while undertaking size judgements of visually-presented objects.Koutstaal et al. (2001) Neuropsychologia
20 Fusiform Laterality Effect Repeated Different > Repeated SameGreater activation (indicating less priming for Different) in:Bilateral fusiform (BA 37, 19).Greater effect of exemplar change in Right than Left fusiform cortex
26 Is Object Priming Response Specific? -15Relation to BehaviorBoth fusiform and PFC “neural priming” scores predictedbehavioral priming scores, each accounting for unique variance.PFC (not fusiform) neural priming predicted size of behavioralslowing that occurred when cue was switched…suggeststhat lack of activity is a marker of automaticity.
27 Is there a correlation between behavioral & neural priming? FrontalTemporalPerceptual-Dobbins et al. (2004)-Maccotta & Buckner (2004)-Lustig & Buckner (2004)-Bergerbest et al. (2005)-Golby et al. (2005)-Oranfidou et al. (2006)-Bunzeck et al. (2006)-Turk-Browne et al. (2006)-Carlesimo et al. (2003)-Dobbins et al. (2004)-Turk-Browne et al. (2006)-later visual cortices
28 A multiple component model of priming Form specificStimulus SpecificityMostLeastSchacter, Wig & Stevens (2007). Curr Opin Neurobiol
29 A multiple component model of priming -Amodal-Priming across abstract representations-Sensitive to changes in stimulus-decision mappingStimulus SpecificityMostLeastSchacter, Wig & Stevens (2007). Curr Opin Neurobiol
30 A multiple component model of priming -Amodal-Priming across abstract representations-Sensitive to changes in stimulus-decision mapping-Most consistently correlated with behaviorStimulus SpecificityMostLeastSchacter, Wig & Stevens (2007). Curr Opin Neurobiol
31 Study PhaseFor each of 3 runs at study, 144 shapes were presented (16 sets of 9 exemplars)Each set alternated in spatial position to the right or left of fixationPres. Time = 2.5 secNonstudiedPrototypeExemplarExemplarInstructions: remember each shape and side of the screenSlotnick Schacter (2004) Nature Neuroscience
33 Nature of visual area activity? Time (sec)% Signal change0.10.2-0.1-0.2481216Left fusiform gyrus (BA37)Old-hitsOld-missesNew-correct rejectionsLate visual regions (BA19, BA37)Ventral View* Old-hits > Old-misses should reflect conscious recollection* Old-hits + Old-misses expected to reflect nonconscious activityTime (sec)% Signal change0.2-0.2481216Left cuneus (BA18)0.4Early visual regions (BA17, BA18)LHOld-hits > Old-missesOld-hits + Old-misses
34 Line Orientation Task*For each shape (at ‘study’ or ‘test’), speeded response whether internal lines sloped:1) upward2) downward*Subjects were not informed that any shapes would be repeated.
35 Line Judgment Task: Old>Related Ventral ViewLeft lingual gyrus (BA18)Time (sec)% Signal change0.1-0.1481216OldRelated0.2* Early visual regions (BA17, BA18)* No late visual region activity (BA19,BA37)LHOld > RelatedXRelated > OldSlotnick & Schacter (2006) Neuropsychologia
36 Line Judgment Task: Behavioral Results **980970960ns950Reaction Time (ms)940930920910OldRelatedNew* p < 0.05Slotnick & Schacter (2006) Neuropsychologia
37 A multiple component model of priming -Amodal-Priming across abstract representations-Sensitive to changes in stimulus-decision mapping-Most consistently correlated with behaviorStimulus SpecificityMostLeastSchacter, Wig & Stevens (2007). Curr Opin Neurobiol