fMRI evidence of word frequency and strength effects during episodic memory encoding

de Zubicaray, Greig I., McMahon, Katie L., Eastburn, Matthew M., Finnigan, Simon and Humphreys, Michael S. (2005) fMRI evidence of word frequency and strength effects during episodic memory encoding. Cognitive Brain Research, 22 3: 439-450. doi:10.1016/j.cogbrainres.2004.10.002

Author de Zubicaray, Greig I.
McMahon, Katie L.
Eastburn, Matthew M.
Finnigan, Simon
Humphreys, Michael S.
Title fMRI evidence of word frequency and strength effects during episodic memory encoding
Journal name Cognitive Brain Research   Check publisher's open access policy
ISSN 0926-6410; 1872-6348; 0006-8993; 0169-328X; 1385-299X; 1872-6240
Publication date 2005-03-01
Sub-type Article (original research)
DOI 10.1016/j.cogbrainres.2004.10.002
Volume 22
Issue 3
Start page 439
End page 450
Total pages 12
Editor F.E. Bloom
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Subject C1
380200 Linguistics
730111 Hearing, vision, speech and their disorders
1109 Neurosciences
Formatted abstract
Word frequency (WF) and strength effects are two important phenomena associated with episodic memory. The former refers to the superior hit-rate (HR) for low (LF) compared to high frequency (HF) words in recognition memory, while the latter describes the incremental effect(s) upon HRs associated with repeating an item at study. Using the subsequent memory method with event-related fMRI, we tested the attention-at-encoding (A-E) [M. Glanzer, J.K. Adams, The mirror effect in recognition memory: data and theory, J. Exp. Psychol.: Learn Mem. Cogn. 16 (1990) 5-16] explanation of the WF effect. In addition to investigating encoding strength, we addressed if study involves accessing prior representations of repeated items via the same mechanism as that at test [J.L. McClelland, M. Chappell, Familiarity breeds differentiation: a subjective-likelihood approach to the effects of experience in recognition memory, Psychol. Rev. 105 (1998) 724-760], entailing recollection [K.J. Malmberg, J.E. Holden, R.M. Shiffirin, Modeling the effects of repetitions, similarity, and normative word frequency on judgments of frequency and recognition memory, J. Exp. Psychol.: Learn Mem. Cogn. 30 (2004) 319-331] and whether less processing effort is entailed for encoding each repetition [M. Cary, L.M. Reder, A dual-process account of the list-length and strength-based mirror effects in recognition, J. Mem. Lang. 49 (2003) 231-248]. The increased BOLD responses observed in the left inferior prefrontal cortex (LIPC) for the WF effect provide support for an AE account. Less effort does appear to be required for encoding each repetition of an item, as reduced BOLD responses were observed in the LIPC and left lateral temporal cortex; both regions demonstrated increased responses in the conventional subsequent memory analysis. At test, a left lateral parietal BOLD response was observed for studied versus unstudied items, while only medial parietal activity was observed for repeated items at study, indicating that accessing prior representations at encoding does not necessarily occur via the same mechanism as that at test, and is unlikely to involve a conscious recall-like process such as recollection. This information may prove useful for constraining cognitive theories of episodic memory.
Keyword Neural basis of behaviour
Word frequency
Episodic memory
Repetition priming
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

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Created: Wed, 15 Aug 2007, 17:19:43 EST