Working Memory Impairments Limitations of Normal Children's in Visual Stimuli Using Event-Related Potentials

Author(s):  
S.Z. Mohd Tumari ◽  
R. Sudirman
2015 ◽  
Vol 74 (6) ◽  
Author(s):  
Siti Zubaidah Mohd Tumari ◽  
Rubita Sudirman

The aim of this study is to examine the working memory impairments imitate age-related between 7 to 12 years old using Event-Related Potentials (ERP) signal. 97 normal children were selected to a visual stimuli assessment (Phase 1 and Phase 2) while their working memory response was recorded using Electroencephalograph (EEG) machine. Raw EEG signal were segmented and averaged into the ERP signal according to the event stimulus occur. Discrete Wavelet Transform technique is preferred to decompose the ERP signal into different frequency band. ERP signal at alpha frequency is used because of alpha is the most prominent component of brain waves activity. The necessary features were extracted as an input for the Logistic Regression (LR) and Support Vector Machine (SVM) classifier. Consequence indicated that the accuracy and mean performance results were significant in predicting either a child had working memory impairment or not. 7 years old have lower accuracy compared to other groups with 60% for LR and 86% for SVM. In conclusion, the study proposed that age-related changes and increasing level of visual stimuli affect working memory impaired. Thus, this study has provided empirical evidence in support for the assumption that younger children have working memory impaired through visual stimuli assessment.  


2018 ◽  
Author(s):  
David De Vito ◽  
Anne E. Ferrey ◽  
Mark J. Fenske ◽  
Naseem Al-Aidroos

Ignoring visual stimuli in the external environment leads to decreased liking of those items; a phenomenon attributed to the affective consequences of attentional inhibition. Here we investigated the generality of this ‘distractor devaluation’ phenomenon by asking whether ignoring stimuli represented internally within visual working memory has the same affective consequences. In two experiments we presented participants with two or three visual stimuli and then, after the stimuli were no longer visible, provided an attentional cue indicating which item in memory was the target they would have to later recall, and which were task-irrelevant distractors. Participants subsequently judged how much they liked these stimuli. Previously-ignored distractors were consistently rated less favorably than targets, replicating prior findings of distractor devaluation. To gain converging evidence, in Experiment 2, we also examined the electrophysiological processes associated with devaluation by measuring individual differences in attention (N2pc) and working memory (CDA) event-related potentials following the attention cue. Larger amplitude of an N2pc-like component was associated with greater devaluation, suggesting that individuals displaying more effective selection of memory targets—an act aided by distractor inhibition—displayed greater levels of distractor devaluation. Individuals showing a larger post-cue CDA amplitude (but not pre-cue CDA amplitude) also showed greater distractor devaluation, supporting prior evidence that visual working-memory resources have a functional role in effecting devaluation. Together, these findings demonstrate that ignoring working-memory representations has affective consequences, and add to the growing evidence that the contribution of selective-attention mechanisms to a wide range of human thought and behaviors leads to devaluation.


2016 ◽  
Vol 78 (7-5) ◽  
Author(s):  
Siti Zubaidah Mohd Tumari ◽  
Rubita Sudirman

This study is to investigate the Event-Related Potentials (ERP) from the background of Electroencephalograph (EEG) signal for working memory retention by using visual stimuli. The proposed analysis of ERP signal is to predict the performance of working memory retention for various frequency bands such as gamma, beta, alpha, theta and delta. This study is intended to process the EEG data into ERP data and analyze the ERP signal based on power spectrum density. This method is applied to data of normal children with age between 7 to 12 years old. Result showed that alpha power band increases during working memory retention towards visual stimuli compared to the other frequency band. 9 years old has the highest amplitude alpha power compared to the other group of age. Therefore, the alpha power band at the prefrontal cortex will be used for the next analysis of the working memory retention.


2002 ◽  
Vol 16 (2) ◽  
pp. 114-118 ◽  
Author(s):  
Timo Ruusuvirta ◽  
Heikki Hämäläinen

Abstract Human event-related potentials (ERPs) to a tone continuously alternating between its two spatial loci of origin (middle-standards, left-standards), to repetitions of left-standards (oddball-deviants), and to the tones originally representing these repetitions presented alone (alone-deviants) were recorded in free-field conditions. During the recordings (Fz, Cz, Pz, M1, and M2 referenced to nose), the subjects watched a silent movie. Oddball-deviants elicited a spatially diffuse two-peaked deflection of positive polarity. It differed from a deflection elicited by left-standards and commenced earlier than a prominent deflection of negative polarity (N1) elicited by alone-deviants. The results are discussed in the context of the mismatch negativity (MMN) and previous findings of dissociation between spatial and non-spatial information in auditory working memory.


2015 ◽  
Vol 27 (3) ◽  
pp. 492-508 ◽  
Author(s):  
Nicholas E. Myers ◽  
Lena Walther ◽  
George Wallis ◽  
Mark G. Stokes ◽  
Anna C. Nobre

Working memory (WM) is strongly influenced by attention. In visual WM tasks, recall performance can be improved by an attention-guiding cue presented before encoding (precue) or during maintenance (retrocue). Although precues and retrocues recruit a similar frontoparietal control network, the two are likely to exhibit some processing differences, because precues invite anticipation of upcoming information whereas retrocues may guide prioritization, protection, and selection of information already in mind. Here we explored the behavioral and electrophysiological differences between precueing and retrocueing in a new visual WM task designed to permit a direct comparison between cueing conditions. We found marked differences in ERP profiles between the precue and retrocue conditions. In line with precues primarily generating an anticipatory shift of attention toward the location of an upcoming item, we found a robust lateralization in late cue-evoked potentials associated with target anticipation. Retrocues elicited a different pattern of ERPs that was compatible with an early selection mechanism, but not with stimulus anticipation. In contrast to the distinct ERP patterns, alpha-band (8–14 Hz) lateralization was indistinguishable between cue types (reflecting, in both conditions, the location of the cued item). We speculate that, whereas alpha-band lateralization after a precue is likely to enable anticipatory attention, lateralization after a retrocue may instead enable the controlled spatiotopic access to recently encoded visual information.


2007 ◽  
Vol 117 (2) ◽  
pp. 259-273 ◽  
Author(s):  
ÜMMÜHAN İŞOĞLU-ALKAÇ ◽  
KARINA KEDZIOR ◽  
GONCA KESKINDEMIRCI ◽  
NUMAN ERMUTLU ◽  
SACIT KARAMURSEL

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