scholarly journals Blinding in tDCS Studies: Correct End-of-Study Guess Does Not Moderate the Effects on Associative and Working Memory

2021 ◽  
Vol 12 (1) ◽  
pp. 58
Author(s):  
Marija Stanković ◽  
Marko Živanović ◽  
Jovana Bjekić ◽  
Saša R. Filipović
Keyword(s):  
Working Memory ◽  
Task Performance ◽  
Direct Current ◽  
Brain Stimulation ◽  
Cognitive Neuroscience ◽  
Memory Performance ◽  
Causal Inferences ◽  
Sham Condition ◽  
Neuroscience Research ◽  
Neural Underpinnings

Transcranial direct current stimulation (tDCS) has become a valuable tool in cognitive neuroscience research as it enables causal inferences about neural underpinnings of cognition. However, studies using tDCS to modulate cognitive functions often yield inconsistent findings. Hence, there is an increasing interest in factors that may moderate the effects, one of which is the participants’ beliefs of the tDCS condition (i.e., real or sham) they received. Namely, whether participants’ correct guessing of sham condition may lead to false-positive tDCS effects. In this study, we aimed to explore if participants’ beliefs about received stimulation type (i.e., the success of blinding) impacted their task performance in tDCS experiments on associative (AM) and working memory (WM). We analyzed data from four within-subject, sham-controlled tDCS memory experiments (N = 83) to check if the correct end-of-study guess of sham condition moderated tDCS effects. We found no evidence that sham guessing moderated post-tDCS memory performance in experiments in which tDCS effects were observed as well as in experiments that showed null effects of tDCS. The results suggest that the correct sham guessing (i.e., placebo-like effect) is unlikely to influence the results in tDCS memory experiments. We discuss the results in light of the growing debate about the relevance and effectiveness of blinding in brain stimulation research.

scholarly journals Working Memory Performance under a Negative Affect Is More Susceptible to Higher Cognitive Workloads with Different Neural Haemodynamic Correlates

2021 ◽  
Vol 11 (7) ◽  
pp. 935
Author(s):  
Ying Xing Feng ◽  
Masashi Kiguchi ◽  
Wei Chun Ung ◽  
Sarat Chandra Dass ◽  
Ahmad Fadzil Mohd Hani ◽  
...  
Keyword(s):  
Working Memory ◽  
Task Performance ◽  
Memory Performance ◽  
Affective State ◽  
Memory Task ◽  
Interactive Effects ◽  
Functional Near Infrared Spectroscopy ◽  
Affective Factors ◽  
Related Stress ◽  
Haemodynamic Activity

The effect of stress on task performance is complex, too much or too little stress negatively affects performance and there exists an optimal level of stress to drive optimal performance. Task difficulty and external affective factors are distinct stressors that impact cognitive performance. Neuroimaging studies showed that mood affects working memory performance and the correlates are changes in haemodynamic activity in the prefrontal cortex (PFC). We investigate the interactive effects of affective states and working memory load (WML) on working memory task performance and haemodynamic activity using functional near-infrared spectroscopy (fNIRS) neuroimaging on the PFC of healthy participants. We seek to understand if haemodynamic responses could tell apart workload-related stress from situational stress arising from external affective distraction. We found that the haemodynamic changes towards affective stressor- and workload-related stress were more dominant in the medial and lateral PFC, respectively. Our study reveals distinct affective state-dependent modulations of haemodynamic activity with increasing WML in n-back tasks, which correlate with decreasing performance. The influence of a negative effect on performance is greater at higher WML, and haemodynamic activity showed evident changes in temporal, and both spatial and strength of activation differently with WML.

Visuospatial Working Memory Deficits and Visual Pursuit Impairments are Not Directly Related in Schizophrenia

2009 ◽  
Vol 43 (8) ◽  
pp. 766-774 ◽  
Author(s):  
Luca Cocchi ◽  
Francesca Bosisio ◽  
Olivia Carter ◽  
Stephen J. Wood ◽  
André Berchtold ◽  
...  
Keyword(s):  
Working Memory ◽  
Task Performance ◽  
Memory Performance ◽  
Correct Choice ◽  
Head Movements ◽  
Visuospatial Working Memory ◽  
Visual Pursuit ◽  
Scanning Time ◽  
Time Scanning ◽  
Correct Path

Objective: Patients with schizophrenia show deficits in visuospatial working memory and visual pursuit processes. It is currently unclear, however, whether both impairments are related to a common neuropathological origin. The purpose of the present study was therefore to examine the possible relations between the encoding and the discrimination of dynamic visuospatial stimuli in schizophrenia. Method: Sixteen outpatients with schizophrenia and 16 control subjects were asked to encode complex disc displacements presented on a screen. After a delay, participants had to identify the previously presented disc trajectory from a choice of six static linear paths, among which were five incorrect paths. The precision of visual pursuit eye movements during the initial presentation of the dynamic stimulus was assessed. The fixations and scanning time in definite regions of the six paths presented during the discrimination phase were investigated. Results: In comparison with controls, patients showed poorer task performance, reduced pursuit accuracy during incorrect trials and less time scanning the correct stimulus or the incorrect paths approximating its global structure. Patients also spent less time scanning the leftmost portion of the correct path even when making a correct choice. The accuracy of visual pursuit and head movements, however, was not correlated with task performance. Conclusions: The present study provides direct support for the hypothesis that active integration of visuospatial information within working memory is deficient in schizophrenia. In contrast, a general impairment of oculomotor mechanisms involved in smooth pursuit did not appear to be directly related to lower visuospatial working memory performance in schizophrenia.

Remembering Over the Short and Long Term

2020 ◽  
pp. 282-310
Author(s):  
Patricia A. Reuter-Lorenz ◽  
Alexandru D. Iordan
Keyword(s):  
Working Memory ◽  
Cognitive Neuroscience ◽  
Semantic Processing ◽  
Long Term Memory ◽  
Strategic Processing ◽  
Term Memory ◽  
Neuroscience Research ◽  
Short And Long Term ◽  
Time Courses

This chapter reviews evidence from behavioural and cognitive neuroscience research that supports a unitary view of memory whereby working memory and long-term memory phenomena arise from representations and processes that are largely shared when remembering over the short or long term. Using ‘false working memories’ as a case study, it highlights several paradoxes that cannot be explained by a multisystem view of memory in which working memory and long-term memory are structurally distinct. Instead, it is posited that behavioural memory effects over the short and long term relating to semantic processing, modality/domain-specificity, dual-task interference, strategic processing, and so on arise from the differences in activational states and availability of different representational features (e.g. sensory/perceptual, associative, action-based) that vary in their time courses and activity, attentional priority, and susceptibility to interference. Cognitive neuroscience evidence primarily from brain imaging methodologies that support this view is reviewed.

scholarly journals Direct-Current Stimulation Does Little to Improve the Outcome of Working Memory Training in Older Adults

2017 ◽  
Vol 28 (7) ◽  
pp. 907-920 ◽  
Author(s):  
Jonna Nilsson ◽  
Alexander V. Lebedev ◽  
Anders Rydström ◽  
Martin Lövdén
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Cognitive Training ◽  
Direct Current ◽  
Memory Performance ◽  
Working Memory Training ◽  
Interactive Effects ◽  
Memory Training ◽  
Older Individuals ◽  
Direct Current Stimulation

The promise of transcranial direct-current stimulation (tDCS) as a modulator of cognition has appealed to researchers, media, and the general public. Researchers have suggested that tDCS may increase effects of cognitive training. In this study of 123 older adults, we examined the interactive effects of 20 sessions of anodal tDCS over the left prefrontal cortex (vs. sham tDCS) and simultaneous working memory training (vs. control training) on change in cognitive abilities. Stimulation did not modulate gains from pre- to posttest on latent factors of either trained or untrained tasks in a statistically significant manner. A supporting meta-analysis ( n = 266), including younger as well as older individuals, showed that, when combined with training, tDCS was not much more effective than sham tDCS at changing working memory performance ( g = 0.07, 95% confidence interval, or CI = [−0.21, 0.34]) and global cognition performance ( g = −0.01, 95% CI = [−0.29, 0.26]) assessed in the absence of stimulation. These results question the general usefulness of current tDCS protocols for enhancing the effects of cognitive training on cognitive ability.

scholarly journals Individual Differences and Long-term Consequences of tDCS-augmented Cognitive Training

2017 ◽  
Vol 29 (9) ◽  
pp. 1498-1508 ◽  
Author(s):  
Benjamin Katz ◽  
Jacky Au ◽  
Martin Buschkuehl ◽  
Tessa Abagis ◽  
Chelsea Zabel ◽  
...  
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Cognitive Training ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Memory Task ◽  
Memory Training ◽  
Direct Current Stimulation ◽  
Sham Condition

A great deal of interest surrounds the use of transcranial direct current stimulation (tDCS) to augment cognitive training. However, effects are inconsistent across studies, and meta-analytic evidence is mixed, especially for healthy, young adults. One major source of this inconsistency is individual differences among the participants, but these differences are rarely examined in the context of combined training/stimulation studies. In addition, it is unclear how long the effects of stimulation last, even in successful interventions. Some studies make use of follow-up assessments, but very few have measured performance more than a few months after an intervention. Here, we utilized data from a previous study of tDCS and cognitive training [Au, J., Katz, B., Buschkuehl, M., Bunarjo, K., Senger, T., Zabel, C., et al. Enhancing working memory training with transcranial direct current stimulation. Journal of Cognitive Neuroscience, 28, 1419–1432, 2016] in which participants trained on a working memory task over 7 days while receiving active or sham tDCS. A new, longer-term follow-up to assess later performance was conducted, and additional participants were added so that the sham condition was better powered. We assessed baseline cognitive ability, gender, training site, and motivation level and found significant interactions between both baseline ability and motivation with condition (active or sham) in models predicting training gain. In addition, the improvements in the active condition versus sham condition appear to be stable even as long as a year after the original intervention.

scholarly journals Emotional Facial Processing: Does Cognitive Load Make a Difference?

2018 ◽  
Author(s):  
Elsie Ong ◽  
Rick Law Tsz Chun
Keyword(s):  
Working Memory ◽  
Cognitive Load ◽  
Task Performance ◽  
Cognitive Processing ◽  
Research Study ◽  
Memory Span ◽  
Memory Performance ◽  
Emotional Faces ◽  
Low Level ◽  
Facial Processing

<p>The manuscript is titled ‘Emotional facial processing: does cognitive load make a difference?’ and it describes a research study that measures how emotion and distraction of different cognitive loads may impact working memory performance. The findings show that cognitive load on working memory performance, with poorer working memory performance in the high compared to the low level of distraction. However, no effects of emotional faces were found on task performance. The work therefore has significance with regard to cognitive processing and working memory span.</p>

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