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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Late positive slow waves as markers of chunking during encoding

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Author(s):
Nogueira, Ana M. L. [1] ; Bueno, Orlando F. A. [1] ; Manzano, Gilberto M. [2] ; Kohn, Andre F. [3] ; Pompeia, Sabine [1]
Total Authors: 5
Affiliation:
[1] Univ Fed Sao Paulo UNIFESP, Dept Psicobiol, BR-0402002 Sao Paulo, SP - Brazil
[2] Univ Fed Sao Paulo UNIFESP, Dept Neurol Neurocirurgia, BR-0402002 Sao Paulo, SP - Brazil
[3] Univ Sao Paulo, Escola Politecn, Dept Engn & Telecomunicacoes & Controle PTC, Lab Engn Biomed, Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: FRONTIERS IN PSYCHOLOGY; v. 6, JUL 28 2015.
Web of Science Citations: 1
Abstract

Electrophysiological markers of chunking of words during encoding have mostly been shown in studies that present pairs of related stimuli. In these cases it is difficult to disentangle cognitive processes that reflect distinctiveness (i.e., conspicuous items because they are related), perceived association between related items and unified representations of various items, or chunking. Here, we propose a paradigm that enables the determination of a separate Event-related Potential (ERP) marker of these cognitive processes using sequentially related word triads. Twenty-three young healthy individuals viewed 80 15-word lists composed of unrelated items except for the three words in the middle serial positions (triads), which could be either unrelated (control list), related perceptually, phonetically or semantically. ERP amplitudes were measured at encoding of each one of the words in the triads. We analyzed two latency intervals (350-400 and 400-800 ms) at midline locations. Behaviorally, we observed a progressive facilitation in the immediate free recall of the words in the triads depending on the relations between their items (control < perceptual < phonetic < semantic), but only semantically related items were recalled as chunks. P300-like deflections were observed for perceptually deviant stimuli. A reduction of amplitude of a component akin to the N400 was found for words that were phonetically and semantically associated with prior items and therefore were not associated to chunking. Positive slow wave (PSVV) amplitudes increased as successive phonetically and semantically related items were presented, but they were observed earlier and were more prominent at Fz for semantic associates. PSWs at Fz and Cz also correlated with recall of semantic word chunks. This confirms prior claims that PSWs at Fz are potential markers of chunking which, in the proposed paradigm, were modulated differently from the detection of deviant stimuli and of relations between stimuli. (AU)