neural correlates of temporal and semantic clustering in...
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0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
R = −0.508p = 0.000
Tem
pora
l fac
tor
Semantic factor
1. Recalled 2. Temporal 3. Semantic
Delta:
2-4 Hz
Theta:
4-8 Hz
Alpha:
10-14 Hz
Beta:
16-26 Hz
Low
Gamma:
28-42 Hz
High
Gamma:
44-100
Hz
REH REL RLH RLL MEH MEL MLH MLL PEH PEL PLH PLL−0.2
−0.15
−0.1
−0.05
0
0.05
0.1
0.15
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ower
(r)ecency (m)iddle (p)rimacy
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0.5 0.6 0.7 0.8 0.9
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0.5
0.6
0.7
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1R = 0.429p = 0.000
Tem
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Probability of Recall
Neural correlates of temporal and semantic clustering in free recallNicole M. Long, Jonathan F. Miller, Per B. Sederberg, Michael J. Kahana University of Pennsylvania, Ohio State University
Introduction
Methods
Behavioral results
EEG results Summary
References
EEG methods
CHAIR CATDOGAPPLE COAT DESK
“CHAIR” “CAT”“COAT” “DOG”“APPLE”“DESK”
study
recall
high semanticlow temporal
low semantichigh temporal
high semantichigh temporal
low semanticlow temporal
Future Directions(1) Power decreases across frequencies for recall(2) Alpha power increases for temporal clustering(3) �eta, alpha, beta power decreases for semantic clustering
Bous�eld, WA (1953) �e occurrence of clustering in the recall of randomly arranged associates. J. Gen. Psych 49: 229-240Kahana, MJ (1996) Associative retrieval processes in free recall. Memory & Cognition 24: 103-109Nelson, DL & McEvoy, CL (2004) �e University of South Florida free association, rhyme and word fragment norms. Beh. Res. Methods 36 (3): 402-407Tulving, E (1962) Subjective organization in free recall of “unrelated” words. Psych Review 69 (4): 344-354�ompson, CP (1972) Organization in memory: Multitrial free recall of categorized word lists. In RF �ompson & JF Voss (Eds.), Topics in learning and performance (pp. 241-263). San Diego, CA: Academic Press
Free recall task where words vary in temporal and semantic relatednessTemporal relatedness determined by lag (di�erence in serial position) High temporal: lag = 1, Low temporal: lag > 2Semantic relatedness determined by word association score (Nelson et al., 2004)
High semantic: WAS > .6, Low semantic: WAS < .2
Organizational processes correlate with successful recall (Tulving, 1962; �ompson, 1972)
Temporal clustering: consecutive recall of nearby study items (Kahana, 2006)
Semantic clustering: consecutive recall of items related in meaning (Bous�eld, 1953)
How do neural mechanisms of temporal and semantic
clustering relate to those associated with recall success?
What mechanisms are shared/di�erent between temporal and semantic
clustering?
Temporal clustering and recency
-Temporal and semantic clustering e�ects in delayed free recall- Interactions between temporal and semantic clustering-Temporal and semantic clustering e�ects during retrieval period
- Successful recall and semantic clustering are both supported by low frequency power increase- Semantic and temporal clustering are supported by di�erent neural mecha-nisms and are negatively correlated behaviorally- Temporal clustering is distinct from recency though both might involve a slowly updating context
Temporal ROI
Recency ROI
Signi�cant temporal clustering e�ects for
primacy (p) serial positions
A 3x2x2 analysis of serial position (recency, middle, primacy) by output position (early, late), by temporal clustering (high, low)
REH REL RLH RLL MEH MEL MLH MLL PEH PEL PLH PLL−0.1
−0.08
−0.06
−0.04
−0.02
0
0.02
0.04
0.06
�et
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Contact: [email protected]
80 participants7 sessions16 lists per session16 words per listScalp EEG 129 electrodesAnalyzed words at encoding as a function of neighbors at recall
Signi�cant output position e�ects without temporal
clustering e�ects