˜e neural correlates of temporal and semantic clustering...
TRANSCRIPT
�e neural correlates of temporal and semantic clustering during retrievalNicole M. Long, Michael J. Kahana
Introduction
Methods
Behavioral results
EEG Oscillatory Power
References
CHAIR CATDOGAPPLE COAT DESK
“CHAIR” “CAT”“COAT” “DOG”“APPLE”“DESK”
study
recall
high semanticlow temporal
low semantichigh temporal
high semantichigh temporal
low semanticlow temporal
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 > .4, Low semantic: WAS < .4
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?
Prob
abili
ty o
f rec
all
Sem
antic
clus
terin
g
Semantic clustering Temporal clusteringTemporal clustering
Summary
EEG Methods: 102 participants | 7 sessions | 16 lists per session | 16 words per list | Scalp EEG, 129 electrodes
Prob
abili
ty o
f rec
all
- Encoding and retrieval mechanisms di�er across all three measurementsRecalled - failure to recall- Encoding: power decreases across frequencies- Retrieval: greater low and high frequency power prior to vocalizationHigh - low temporal clustering- Encoding: theta power decreases, alpha power increases- Retrieval: early power increases; pre-vocalization power decreasesHigh - low semantic clustering- Encoding: low frequency power decreases- Retrieval: early power increases; pre-vocalization power decreases which begin earlier than temporal
Probability of recall positively correlated with temporal clustering
Temporal and semantic clustering are negatively correlated
Recalled - failure to recall
High - Low Temporal Clustering
High - Low Semantic Clustering
EncodingLe� Right
0 500 1000 1500
99
35
12
40 500 1000 1500
0 500 1000 1500
99
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12
40 500 1000 1500
0 500 1000 1500
99
35
12
40 500 1000 1500
−1500 −1000 −500 0
99
35
12
4−1500 −1000 −500 0
RetrievalLe� Right
−1500 −1000 −500 0
99
35
12
4−1500 −1000 −500 0
−1500 −1000 −500 0
99
35
12
4−1500 −1000 −500 0
AS
AI
PI
Retrieval dynamics
−1500 −1000 −500 0
1
2
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6
−1500 −1000 −500 0 −1500 −1000 −500 0
Recall
Power increasesPower decreases
�etaGamma
Temporal clustering Semantic clustering
# Si
gni�
cant
RO
Is
Time from word onset (ms)
Freq
uenc
y
AS
AI
PIFr
eque
ncy
EncodingLe� Right
RetrievalLe� Right
EncodingLe� Right
RetrievalLe� Right
AS
AI
PI
Freq
uenc
y
Delta Z-power-.1 .10-.05 .05
Anterior SuperiorAnterior Inferior
Posterior Inferior
Time preceding vocalization (ms)
Time from word onset (ms) Time preceding vocalization (ms)
Time from word onset (ms) Time preceding vocalization (ms)0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.90.54
0.56
0.58
0.6
0.62
0.64
0.66
0.68
0.54 0.56 0.58 0.6 0.62 0.64 0.66 0.68
0.4
0.5
0.6
0.7
0.8
0.9
1
0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9
0.4
0.5
0.6
0.7
0.8
0.9
1
R =.39P < .01
R =.15P = .12
R = -.27P < .01
Time preceding vocalization (ms)