priming, implicit memory, and the brain: a neuroimaging perspective daniel l. schacter
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Priming, Implicit Memory, and the Brain: A Neuroimaging Perspective Daniel L. Schacter Harvard University. Acknowledgements. Memory Lab, Harvard Psychology Donna Addis Elissa Aminoff Elizabeth Chua Rachel Garoff-Eaton Angela Gutchess Dale Stevens Gagan Wig Alana Wong - PowerPoint PPT PresentationTRANSCRIPT
Priming, Implicit Memory, and the Brain:
A Neuroimaging Perspective
Daniel L. Schacter Harvard University
Acknowledgements
Memory Lab, Harvard Psychology
Donna Addis
Elissa Aminoff
Elizabeth Chua
Rachel Garoff-Eaton
Angela Gutchess
Dale Stevens
Gagan Wig
Alana Wong
Athinoula A. Martinos Center for Biomedical Imaging
Supported by NIMH and NIA
MYSTERY
APRICOT
CUPCAKE
ASSASSIN
_ _ES_ _X
_UP_ _KE
Tulving, Schacter, & Stark (1982)
Picture Fragment ID after 17 Years
(M Age = 39.2; Mitchell, 2006)
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70
Old New
Some Properties of Priming on Stem Completion, Fragment Completion and Identification Tests
*Unaffected or even reduced by semantic or elaborative encoding manipulations that enhance recall and recognition.
*Sensitive to changes between study and test in the physical features of target items: sensory modality, word font, case. Such changes typically have smaller effects on recall and recognition.
*Typically preserved in amnesic patients with impairments on recall and reocgnition tests.
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 of words/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.
Object Priming Paradigm
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STUDY TEST
2 SECBETWEENSTIMULI
Behavioral Performance at Test
NOVEL REPEATED 0
450
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700
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900
RE
AC
TIO
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IME
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SE
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Novel > Repeated Same
• Left anterior inferior frontal cortex (BA 47, 45)
• Bilateral fusiform, extending into parahippocampal cortex (BA 37, 19)
Reduced activation (indicating priming) for repeated objects in multiple regions, including:
Priming-related activation decreases
Specificity of Priming-Related Specificity of Priming-Related ReductionsReductions
Neural correlates of priming for:
• Novel objects
• Repeated same objects
• Repeated different objects
18 subjects scanned while undertaking size judgements of visually-presented objects.
Koutstaal et al. (2001) Neuropsychologia
Fusiform Laterality EffectFusiform Laterality Effect
Repeated Different > Repeated SameRepeated Different > Repeated Same
• Bilateral fusiform (BA 37, 19).
• Greater effect of exemplar change in Right than Left fusiform cortex
Greater activation (indicating less priming for Different) in:
Explaining Activation Decrease in Object Priming
Wiggs, C. L., & Martin, A. (1998). Properties and mechanisms of perceptual priming. Current Opinion in Neurobiology.
“Neural Tuning”
High PrimeNovel
“Bigger than a shoebox? (yes/no)”
1.Start Phase
2.Switch Phase
“Smaller than a shoebox? (yes/no)”
High PrimeNovel
Novel Low Primed High Primed
3.Return Phase
“Bigger than a shoebox? (yes/no)”
Low Primed Novel High Primed
Low PrimeNovel Novel Low Prime
n = 16, Event Related, 4 - Cycles
Is Object Priming Response Specific?
Dobbins, Schnyer, Verfaellie & Schacter (2004) Nature
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Cue Reversal - fMRINovel Low High
Start Switch Return
Mea
n R
eact
ion
Tim
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mill
isec
onds
a
Is Object Priming Response Specific?
Dobbins, Schnyer, Verfaellie & Schacter (2004) Nature
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Start Switch Return
Mean “Neural Priming”
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0.04
0.08
0.12
-0.02
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0.02
0.04
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0.08
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0.12
PFC
Fusiform
Is Object Priming Response Specific?
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PFC
Fusiform
Start Switch Return
ForgettingControl
Dobbins, Schnyer, Verfaellie & Schacter (2004) Nature
Is Object Priming Response Specific?
Relation to Behavior
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Both 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.
Frontal Temporal Perceptual
-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)
Is there a correlation between behavioral & neural priming?
-Dobbins et al. (2004)
-Turk-Browne et al. (2006)
A
Stimulus Specificity
MostLeast
LR
Schacter, Wig & Stevens (2007). Curr Opin Neurobiol
A multiple component model of priming
A
D
A
Stimulus Specificity
MostLeast
LR
Schacter, Wig & Stevens (2007). Curr Opin Neurobiol
A multiple component model of priming
-Amodal
-Priming across abstract representations
-Sensitive to changes in stimulus-decision mapping
A
D
A
Stimulus Specificity
MostLeast
LR
Schacter, Wig & Stevens (2007). Curr Opin Neurobiol
A multiple component model of priming
-Amodal
-Priming across abstract representations
-Sensitive to changes in stimulus-decision mapping
-Most consistently correlated with behavior
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 fixation
Pres. Time = 2.5 sec
Instructions: remember each shape and side of the screen
NonstudiedPrototype Exemplar Exemplar
Slotnick Schacter (2004) Nature Neuroscience
True recognition > False recognition
Old-hits > Related-false alarms
Related-false alarms > Old-hits
Ventral View
LH
Early visual regions (BA17, BA18)
Time (sec)
% S
igna
l cha
nge
00.10.20.3
-0.1-0.2-0.3
0 4 8 12 16
Left fusiform gyrus (BA18)
Old-hitsRelated-false alarms
X
LH
Old-hits > Old-misses
Old-hits + Old-misses
Nature of visual area activity?
* Old-hits > Old-misses should reflect conscious recollection
Time (sec)
% S
igna
l cha
nge
00.10.2
-0.1-0.2
0 4 8 12 16
Left fusiform gyrus (BA37)
Old-hitsOld-missesNew-correct rejections
Late visual regions (BA19, BA37)
* Old-hits + Old-misses expected to reflect nonconscious activity
Time (sec)
% S
igna
l cha
nge
0
0.2
-0.2
0 4 8 12 16
Left cuneus (BA18)
0.4
Early visual regions (BA17, BA18)
Ventral View
Line Orientation Task*For each shape (at ‘study’ or ‘test’), speeded
response whether internal lines sloped:
1) upward
2) downward
*Subjects were not informed that any shapes would be repeated.
Line Judgment Task: Old>Related
Ventral View
* Early visual regions (BA17, BA18)
Old > Related
Related > OldX
LH
Left lingual gyrus (BA18)
Time (sec)
% S
igna
l cha
nge
0
0.1
-0.1
0 4 8 12 16
OldRelated
0.2
* No late visual region activity (BA19,BA37)
Slotnick & Schacter (2006) Neuropsychologia
Line Judgment Task: Behavioral Results
Old Related New
Rea
ctio
n T
ime
(ms)
910
920
930
940
950
960
970
980
ns
* p < 0.05
**
Slotnick & Schacter (2006) Neuropsychologia
A
D
A
Stimulus Specificity
MostLeast
LR
Schacter, Wig & Stevens (2007). Curr Opin Neurobiol
A multiple component model of priming
-Amodal
-Priming across abstract representations
-Sensitive to changes in stimulus-decision mapping
-Most consistently correlated with behavior