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Kouwenhoven M, Machado L. Age differences in inhibitory and working memory functioning: limited evidence of system interactions. NEUROPSYCHOLOGY, DEVELOPMENT, AND COGNITION. SECTION B, AGING, NEUROPSYCHOLOGY AND COGNITION 2024; 31:524-555. [PMID: 37195032 DOI: 10.1080/13825585.2023.2214348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 05/10/2023] [Indexed: 05/18/2023]
Abstract
Debate persists regarding the nature of age-related deficits in inhibition, and whether inhibitory functioning depends on working memory systems. The current research aimed to measure age-related differences in inhibition and working memory, characterize the relationship between inhibitory functions and working memory performance, and determine how these relationships are affected by age. Toward these ends, we measured performance on a range of established paradigms in 60 young adults (18-30 years) and 60 older adults (60-88 years). Our findings support age-related increases in reflexive inhibition (based on the fixation offset effect and inhibition of return) and age-related decrements in volitional inhibition (based on several paradigms: antisaccade, Stroop, flanker, and Simon). This evidence of stronger reflexive inhibition combined with weaker volitional inhibition suggests that age-related deterioration of cortical structures may allow subcortical structures to operate less controlled. Regarding working memory, older adults had lower backward digit scores and lower forward and backward spatial scores. However, of the 32 analyses (16 in each age group) that tested for dependence of inhibitory functioning on working memory functioning, only one (in young adults) indicated that inhibition performance significantly depended on working memory performance. These results indicate that inhibition and working memory function largely independently in both age groups, and age-related working memory difficulties cannot account for age-related declines in inhibitory control.
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Affiliation(s)
| | - Liana Machado
- Department of Psychology, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand, Auckland, New Zealand
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2
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Aksu S, Hasırcı Bayır BR, Sayman C, Soyata AZ, Boz G, Karamürsel S. Working memory ımprovement after transcranial direct current stimulation paired with working memory training ın diabetic peripheral neuropathy. APPLIED NEUROPSYCHOLOGY. ADULT 2023:1-14. [PMID: 36630270 DOI: 10.1080/23279095.2022.2164717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Association of cognitive deficits and diabetic peripheral neuropathy (DPN) is frequent. Working memory (WM) deficits result in impairment of daily activities, diminished functionality, and treatment compliance. Mounting evidence suggests that transcranial Direct Current Stimulation (tDCS) with concurrent working memory training (WMT) ameliorates cognitive deficits. Emboldening results of tDCS were shown in DPN. The study aimed to evaluate the efficacy of anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC) coupled with cathodal right DLPFC with concurrent WMT in DPN for the first time. The present randomized triple-blind parallel-group sham-controlled study evaluated the efficacy of 5 sessions of tDCS over the DLPFC concurrent with WMT in 28 individuals with painful DPN on cognitive (primary) and pain-related, psychiatric outcome measures before, immediately after, and 1-month after treatment protocol. tDCS enhanced the efficacy of WMT on working memory and yielded lower anxiety levels than sham tDCS but efficacy was not superior to sham on other cognitive domains, pain severity, quality of life, and depression. tDCS with concurrent WMT enhanced WM and ameliorated anxiety in DPN without affecting other cognitive and pain-related outcomes. Further research scrutinizing the short/long-term efficacy with larger samples is accredited.
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Affiliation(s)
- Serkan Aksu
- Department of Physiology, Faculty of Medicine, Muğla Sıtkı Koçman University, Muğla, Türkiye
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Buse Rahime Hasırcı Bayır
- Department of Neurology, Health Sciences University, Haydarpaşa Numune Education and Research Hospital, Istanbul, Türkiye
| | - Ceyhun Sayman
- Translational Neurodevelopmental Neuroscience Phd Programme, Institute of Health Science, Istanbul University, Istanbul, Türkiye
| | - Ahmet Zihni Soyata
- Psychiatry Outpatient Clinic, Başakşehir State Hospital, İstanbul, Turkey
| | - Gökalp Boz
- Department of Psychology, Istanbul University, Istanbul, Türkiye
| | - Sacit Karamürsel
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
- Department of Physiology, School of Medicine, Koc University, Istanbul, Türkiye
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3
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Assecondi S, Hu R, Kroeker J, Eskes G, Shapiro K. Older adults with lower working memory capacity benefit from transcranial direct current stimulation when combined with working memory training: A preliminary study. Front Aging Neurosci 2022; 14:1009262. [PMID: 36299611 PMCID: PMC9589058 DOI: 10.3389/fnagi.2022.1009262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/20/2022] [Indexed: 11/27/2022] Open
Abstract
Aging is a very diverse process: successful agers retain most cognitive functioning, while others experience mild to severe cognitive decline. This decline may eventually negatively impact one’s everyday activities. Therefore, scientists must develop approaches to counteract or, at least, slow down the negative change in cognitive performance of aging individuals. Combining cognitive training and transcranial direct current stimulation (tDCS) is a promising approach that capitalizes on the plasticity of brain networks. However, the efficacy of combined methods depends on individual characteristics, such as the cognitive and emotional state of the individual entering the training program. In this report, we explored the effectiveness of working memory training, combined with tDCS to the right dorsolateral prefrontal cortex (DLPFC), to manipulate working memory performance in older individuals. We hypothesized that individuals with lower working memory capacity would benefit the most from the combined regimen. Thirty older adults took part in a 5-day combined regimen. Before and after the training, we evaluated participants’ working memory performance with five working memory tasks. We found that individual characteristics influenced the outcome of combined cognitive training and tDCS regimens, with the intervention selectively benefiting old-old adults with lower working memory capacity. Future work should consider developing individualized treatments by considering individual differences in cognitive profiles.
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Affiliation(s)
- Sara Assecondi
- Center for Mind/Brain Sciences—CIMeC, University of Trento, Rovereto, Italy
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, United Kingdom
- *Correspondence: Sara Assecondi, ,
| | - Rong Hu
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Department of Neurology, School of Medicine, Guangzhou First People’s Hospital, South China University of Technology, Guangzhou, China
| | - Jacob Kroeker
- Departments of Psychiatry and Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Gail Eskes
- Departments of Psychiatry and Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Kim Shapiro
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, United Kingdom
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Assecondi S, Villa-Sánchez B, Shapiro K. Event-Related Potentials as Markers of Efficacy for Combined Working Memory Training and Transcranial Direct Current Stimulation Regimens: A Proof-of-Concept Study. Front Syst Neurosci 2022; 16:837979. [PMID: 35547238 PMCID: PMC9083230 DOI: 10.3389/fnsys.2022.837979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/28/2022] [Indexed: 11/14/2022] Open
Abstract
Our brains are often under pressure to process a continuous flow of information in a short time, therefore facing a constantly increasing demand for cognitive resources. Recent studies have highlighted that a lasting improvement of cognitive functions may be achieved by exploiting plasticity, i.e., the brain’s ability to adapt to the ever-changing cognitive demands imposed by the environment. Transcranial direct current stimulation (tDCS), when combined with cognitive training, can promote plasticity, amplify training gains and their maintenance over time. The availability of low-cost wearable devices has made these approaches more feasible, albeit the effectiveness of combined training regimens is still unclear. To quantify the effectiveness of such protocols, many researchers have focused on behavioral measures such as accuracy or reaction time. These variables only return a global, non-specific picture of the underlying cognitive process. Electrophysiology instead has the finer grained resolution required to shed new light on the time course of the events underpinning processes critical to cognitive control, and if and how these processes are modulated by concurrent tDCS. To the best of our knowledge, research in this direction is still very limited. We investigate the electrophysiological correlates of combined 3-day working memory training and non-invasive brain stimulation in young adults. We focus on event-related potentials (ERPs), instead of other features such as oscillations or connectivity, because components can be measured on as little as one electrode. ERP components are, therefore, well suited for use with home devices, usually equipped with a limited number of recording channels. We consider short-, mid-, and long-latency components typically elicited by working memory tasks and assess if and how the amplitude of these components are modulated by the combined training regimen. We found no significant effects of tDCS either behaviorally or in brain activity, as measured by ERPs. We concluded that either tDCS was ineffective (because of the specific protocol or the sample under consideration, i.e., young adults) or brain-related changes, if present, were too subtle. Therefore, we suggest that other measures of brain activity may be more appropriate/sensitive to training- and/or tDCS-induced modulations, such as network connectivity, especially in young adults.
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Affiliation(s)
- Sara Assecondi
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
- *Correspondence: Sara Assecondi, ,
| | | | - Kim Shapiro
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
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Orcioli-Silva D, Islam A, Baker MR, Gobbi LTB, Rochester L, Pantall A. Bi-Anodal Transcranial Direct Current Stimulation Combined With Treadmill Walking Decreases Motor Cortical Activity in Young and Older Adults. Front Aging Neurosci 2021; 13:739998. [PMID: 34924993 PMCID: PMC8681021 DOI: 10.3389/fnagi.2021.739998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/01/2021] [Indexed: 01/05/2023] Open
Abstract
Background: Walking in the "real world" involves motor and cognitive processes. In relation to this, declines in both motor function and cognition contribute to age-related gait dysfunction. Transcranial direct current stimulation (tDCS) and treadmill walking (STW) have potential to improve gait, particularly during dual-task walking (DTW); walking whilst performing a cognitive task. Our aims were to analyze effects of combined anodal tDCS + STW intervention on cortical activity and gait during DTW. Methods: Twenty-three young adults (YA) and 21 older adults (OA) were randomly allocated to active or sham tDCS stimulation groups. Participants performed 5-min of mixed treadmill walking (alternating 30 s bouts of STW and DTW) before and after a 20-min intervention of active or sham tDCS + STW. Anodal electrodes were placed over the left prefrontal cortex (PFC) and the vertex (Cz) using 9 cm2 electrodes at 0.6 mA. Cortical activity of the PFC, primary motor cortex (M1), premotor cortex (PMC), and supplementary motor area (SMA) bilaterally were recorded using a functional near-infrared spectroscopy (fNIRS) system. Oxygenated hemoglobin (HbO2) levels were analyzed as indicators of cortical activity. An accelerometer measured gait parameters. We calculated the difference between DTW and STW for HbO2 and gait parameters. We applied linear mixed effects models which included age group (YA vs. OA), stimulation condition (sham vs. active), and time (pre- vs. post-intervention) as fixed effects. Treadmill belt speed was a covariate. Partial correlation tests were also performed. Results: A main effect of age group was observed. OA displayed higher activity bilaterally in the PFC and M1, unilaterally in the right PMC and higher gait variability than YA. M1 activity decreased in both YA and OA following active tDCS + STW. There was no overall effect of tDCS + STW on PFC activity or gait parameters. However, negative correlations were observed between changes in left PFC and stride length variability following active tDCS + STW intervention. Conclusion: Increased activity in multiple cortical areas during DTW in OA may act as a compensatory mechanism. Reduction in M1 activity following active tDCS + STW with no observed gait changes suggests improved neural efficiency.
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Affiliation(s)
- Diego Orcioli-Silva
- Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil.,Graduate Program in Movement Sciences, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Aisha Islam
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mark R Baker
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Lilian Teresa Bucken Gobbi
- Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil.,Graduate Program in Movement Sciences, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Lynn Rochester
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Annette Pantall
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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Savoury R, Kibele A, Behm DG. Methodological Issues with Transcranial Direct Current Stimulation for Enhancing Muscle Strength and Endurance: A Narrative Review. JOURNAL OF COGNITIVE ENHANCEMENT 2021. [DOI: 10.1007/s41465-021-00222-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Smits FM, Schutter DJLG, van Honk J, Geuze E. Does non-invasive brain stimulation modulate emotional stress reactivity? Soc Cogn Affect Neurosci 2021; 15:23-51. [PMID: 31993648 PMCID: PMC7171378 DOI: 10.1093/scan/nsaa011] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 12/09/2019] [Accepted: 01/08/2020] [Indexed: 12/14/2022] Open
Abstract
Excessive emotional responses to stressful events can detrimentally affect psychological functioning and mental health. Recent studies have provided evidence that non-invasive brain stimulation (NBS) targeting the prefrontal cortex (PFC) can affect the regulation of stress-related emotional responses. However, the reliability and effect sizes have not been systematically analyzed. In the present study, we reviewed and meta-analyzed the effects of repetitive transcranial magnetic (rTMS) and transcranial direct current stimulation (tDCS) over the PFC on acute emotional stress reactivity in healthy individuals. Forty sham-controlled single-session rTMS and tDCS studies were included. Separate random effects models were performed to estimate the mean effect sizes of emotional reactivity. Twelve rTMS studies together showed no evidence that rTMS over the PFC influenced emotional reactivity. Twenty-six anodal tDCS studies yielded a weak beneficial effect on stress-related emotional reactivity (Hedges’ g = −0.16, CI95% = [−0.33, 0.00]). These findings suggest that a single session of NBS is insufficient to induce reliable, clinically significant effects but also provide preliminary evidence that specific NBS methods can affect emotional reactivity. This may motivate further research into augmenting the efficacy of NBS protocols on stress-related processes.
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Affiliation(s)
- Fenne M Smits
- Brain Research & Innovation Centre, Ministry of Defence, Lundlaan 1, 3584 EZ, Utrecht, The Netherlands.,Department of Psychiatry, UMC Utrecht Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Dennis J L G Schutter
- Experimental Psychology, Helmholtz Institute, Utrecht University, Heidelberglaan 1, 3584 CS, Utrecht, The Netherlands
| | - Jack van Honk
- Experimental Psychology, Helmholtz Institute, Utrecht University, Heidelberglaan 1, 3584 CS, Utrecht, The Netherlands.,Department of Psychiatry and Mental Health, University of Cape Town, Observatory, 7925, Cape Town, South Africa.,Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, 7925, Cape Town, South Africa
| | - Elbert Geuze
- Brain Research & Innovation Centre, Ministry of Defence, Lundlaan 1, 3584 EZ, Utrecht, The Netherlands.,Department of Psychiatry, UMC Utrecht Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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White N, Kouwenhoven M, Machado L. Short-Term Retest Performance in Young versus Older Adults: Consideration of Integrated Speed-Accuracy Measures. Exp Aging Res 2021; 48:68-85. [PMID: 33993852 DOI: 10.1080/0361073x.2021.1919475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Objectives: The current research addressed gaps in the literature regarding short-term computerized cognitive retest performance in young and older adults using two integrated speed-accuracy metrics. The aims were: (a) to advance the aging literature on short-term retest performance using a computerized cognitive battery and a retest schedule that included both within- and between-day time points, and (b) to assess the test-retest reliability of two integrated speed-accuracy metrics, inverse efficiency scores (IES) and balanced integration scores (BIS).Method: Twenty young (18-23 years) and thirty older (65-71 years) men completed a battery measuring a range of cognitive functions, six times over three testing days, each 1 week apart.Results: Compared to young adults, older adults exhibited steeper within- and between-day performance gains in IES and BIS, which may reflect a combination of lower initial cognitive ability and familiarity, indicating that older adults may require more familiarization on computerized tests. Relative to unadjusted reaction times, IES reliability appeared comparable in older adults, but slightly lower among young adults. The reliability of BIS was lower than unadjusted reaction times and IES in both age groups.Discussion: Our findings provide guidance for researchers wanting to combine speed and accuracy into a single performance metric in repeated testing contexts.
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Affiliation(s)
- Naomi White
- Department of Psychology, University of Otago, Dunedin, New Zealand.,Brain Research New Zealand, Auckland, New Zealand
| | | | - Liana Machado
- Department of Psychology, University of Otago, Dunedin, New Zealand.,Brain Research New Zealand, Auckland, New Zealand
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Assecondi S, Hu R, Eskes G, Pan X, Zhou J, Shapiro K. Impact of tDCS on working memory training is enhanced by strategy instructions in individuals with low working memory capacity. Sci Rep 2021; 11:5531. [PMID: 33750803 PMCID: PMC7943602 DOI: 10.1038/s41598-021-84298-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 02/09/2021] [Indexed: 11/09/2022] Open
Abstract
Interventions to improve working memory, e.g. by combining task rehearsal and non-invasive brain stimulation, are gaining popularity. Many factors, however, affect the outcome of these interventions. We hypothesize that working memory capacity at baseline predicts how an individual performs on a working memory task, by setting limits on the benefit derived from tDCS when combined with strategy instructions; specifically, we hypothesize that individuals with low capacity will benefit the most. Eighty-four participants underwent two sessions of an adaptive working memory task (n-back) on two consecutive days. Participants were split into four independent groups (SHAM vs ACTIVE stimulation and STRATEGY vs no STRATEGY instructions). For the purpose of analysis, individuals were divided based on their baseline working memory capacity. Results support our prediction that the combination of tDCS and strategy instructions is particularly beneficial in low capacity individuals. Our findings contribute to a better understanding of factors affecting the outcome of tDCS when used in conjunction with cognitive training to improve working memory. Moreover, our results have implications for training regimens, e.g., by designing interventions predicated on baseline cognitive abilities, or focusing on strategy development for specific attentional skills.
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Affiliation(s)
- Sara Assecondi
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, UK. .,Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, UK.
| | - Rong Hu
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, UK.,Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, UK.,Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
| | - Gail Eskes
- Departments of Psychiatry and Psychology & Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Xiaoping Pan
- Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
| | - Jin Zhou
- Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
| | - Kim Shapiro
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, UK.,Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, UK
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A Comprehensive Meta-analysis on Short-term and Working Memory Dysfunction in Parkinson's Disease. Neuropsychol Rev 2021; 31:288-311. [PMID: 33523408 DOI: 10.1007/s11065-021-09480-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/05/2021] [Indexed: 12/29/2022]
Abstract
A previous meta-analysis demonstrated short-term memory (STM) and working memory (WM) dysfunction in patients with Parkinson's disease (PD). However, considerable research on the topic that calls into question the extent of such impairments in PD has since been published. The aim of the present quantitative review was to provide the largest statistical overview on STM and WM dysfunction in Parkinson's disease (PD), while simultaneously providing novel insights on moderating factors of effect size heterogeneity in PD. The systematic literature search in PubMed, PsycINFO, PsycArticles, Scopus and Web of Science databases allowed us to estimate 350 effect sizes from 145 empirical studies that reported STM and WM scores for patients with PD against healthy controls. The outcomes indicated general dysfunction in the visuospatial domain and poor verbal WM in PD. Subgroup analyses suggested that mild cognitive impairment is associated with STM and WM difficulties in PD. Furthermore, meta-regression analyses revealed that disease duration accounted for more than 80% of the visuospatial STM effect size variance (β = 0.136, p < .001, R2 = .8272), larger daily levodopa equivalent dose was associated with WM dysfunction (verbal: β = -0.001, p = .016, R2 = .1812; visuospatial: β = 0.003, p = .069, R2 = .2340), and years of education partially explained the verbal STM effect size variance (β = -0.027, p = .040, R2 = .1171). Collectively, these findings advance our understanding of underlying factors that influence STM and WM functioning in PD, while at the same time providing novel directions for future research.
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London RE, Slagter HA. No Effect of Transcranial Direct Current Stimulation over Left Dorsolateral Prefrontal Cortex on Temporal Attention. J Cogn Neurosci 2021; 33:756-768. [PMID: 33464163 DOI: 10.1162/jocn_a_01679] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Selection mechanisms that dynamically gate only relevant perceptual information for further processing and sustained representation in working memory are critical for goal-directed behavior. We examined whether this gating process can be modulated by transcranial direct current stimulation (tDCS) over left dorsolateral prefrontal cortex (lDLPFC)-a region known to play a key role in working memory and conscious access. Specifically, we examined the effects of tDCS on the magnitude of the "attentional blink" (AB), a deficit in identifying the second of two targets presented in rapid succession. Thirty-four participants performed an AB task before (baseline), during and after 20 min of 1-mA anodal and cathodal tDCS in two separate sessions. On the basis of previous reports linking individual differences in AB magnitude to individual differences in DLPFC activity and on the basis of suggestions that effects of tDCS depend on baseline brain activity levels, we hypothesized that anodal tDCS over lDLPFC would modulate the magnitude of the AB as a function of individual baseline AB magnitude. Behavioral results did not provide support for this hypothesis. At the group level, we also did not observe any significant effects of tDCS, and a Bayesian analysis revealed strong evidence that tDCS to lDLPFC did not affect AB performance. Together, these findings do not support the idea that there is an optimal level of prefrontal cortical excitability for cognitive function. More generally, they add to a growing body of work that challenges the idea that the effects of tDCS can be predicted from baseline levels of behavior.
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12
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Machado L. Understanding cognition and how it changes with aging, brain disease, and lifestyle choices. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1796102] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Liana Machado
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand, Auckland, New Zealand
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13
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Pourmajidian M, Lauber B, Sidhu SK. Preconditioning cathodal transcranial direct current stimulation facilitates the neuroplastic effect of subsequent anodal transcranial direct current stimulation applied during cycling in young adults. Neurosci Lett 2020; 714:134597. [PMID: 31689457 DOI: 10.1016/j.neulet.2019.134597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 10/11/2019] [Accepted: 10/28/2019] [Indexed: 01/30/2023]
Abstract
The study aimed to examine the effect of a pre-conditioning cathodal transcranial direct current stimulation (ctDCS) before subsequent anodal-tDCS (atDCS) was applied during low workload cycling exercise on the corticospinal responses in young healthy individuals. Eleven young subjects participated in two sessions receiving either conditioning ctDCS or sham stimulation, followed by atDCS while cycling (i.e. ctDCS-atDCS, sham-atDCS) at 1.2 times their body weight (84 ± 20 W) in a counterbalanced double-blind design. Corticospinal excitability was measured with motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation with the intensity set to produce an MEP amplitude of 1 mV in a resting hand muscle at baseline (PRE), following pre-conditioning tDCS (POST-COND) and post atDCS combined with cycling exercise (POST-TEST). There was a significant interaction between time and intervention (P < 0.01) on MEPs. MEPs increased from PRE (1.0 ± 0.06 mV) to POST-TEST (1.3 ± 0.06 mV) during ctDCS-atDCS (P < 0.001) but did not change significantly across time during sham-atDCS (P > 0.7). Furthermore, MEPs were higher in ctDCS-atDCS compared to sham-atDCS (both P < 0.01) at POST-COND (ctDCS-atDCS: 1.1 ± 0.06 mV, sham-atDCS: 1.0 ± 0.06 mV) and POST-TEST (ctDCS-atDCS: 1.3 ± 0.06 mV, sham-atDCS: 1.0 ± 0.06 mV). These outcomes demonstrate that pre-conditioning cathodal tDCS can enhance subsequent corticospinal excitability changes induced by anodal tDCS applied in combination with cycling exercise. The findings have implications for the application of tDCS in combination with cycling exercise in rehabilitation and sporting contexts.
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Affiliation(s)
- Maryam Pourmajidian
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - Benedikt Lauber
- Department of Neuroscience and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Simranjit K Sidhu
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia.
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Zhou M, Chen X, Chen W, Bai X. Stimulating the left dorsolateral prefrontal cortex improves the memory representation of threats among individuals with high avoidant attachment. Behav Brain Res 2019; 373:112073. [PMID: 31326509 DOI: 10.1016/j.bbr.2019.112073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/27/2019] [Accepted: 07/03/2019] [Indexed: 10/26/2022]
Abstract
Prior research has suggested that individuals with high avoidant attachment may demonstrate a vigilant attentional bias and selective attentional avoidance towards attachment-related negative information (threat information). Similarly, some evidence suggests that impairment of hot working memory (WM) or emotional-related WM occurs in highly avoidant individuals. Moreover, functional MRI studies have demonstrated that the less-activated left dorsolateral prefrontal cortex (L-DLPFC) is related to the impairment of cognitive control for threat stimuli in individuals with high avoidant attachment. Therefore, in the present study, the causal role of the L-DLPFC on hot WM presentation was investigated by the high-definition transcranial direct current stimulation (HD-tDCS) technique, and cognitive control for internal mental representations in WM was measured by the Internal Shift Task (IST). The results showed that the highly avoidant participants performed faster on the emotional IST than low avoidant participants in the sham condition. In the emotional IST, highly avoidant participants were slower after receiving anodal HD-tDCS than in the sham condition. Moreover, the switching cost of the emotional IST was significantly smaller in the highly avoidant group than low avoidant group under the sham HD-tDCS condition. Interestingly, in the emotional IST, the switching cost of highly avoidant individuals was significantly greater in the anodal stimulation group than the sham stimulation group. Conversely, the switching cost of low avoidant individuals was significantly smaller with anodal stimulation than for sham stimulation. The findings indicate that anodal HD-tDCS over the L-DLPFC can effectively enhance the ability of memory representation towards threat information in highly avoidant individuals. This study extends causal research by showing that the L-DLPFC is an important brain region for hot WM representations.
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Affiliation(s)
- Mi Zhou
- Faculty of Psychology, Southwest University, Chongqing, China; Key Laboratory of Cognition and Personality, Ministry of Education, Southwest University, Chongqing, China
| | - Xu Chen
- Faculty of Psychology, Southwest University, Chongqing, China; Key Laboratory of Cognition and Personality, Ministry of Education, Southwest University, Chongqing, China.
| | - Wanting Chen
- Faculty of Psychology, Southwest University, Chongqing, China; Key Laboratory of Cognition and Personality, Ministry of Education, Southwest University, Chongqing, China
| | - Xujia Bai
- Faculty of Psychology, Southwest University, Chongqing, China; Key Laboratory of Cognition and Personality, Ministry of Education, Southwest University, Chongqing, China
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15
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Access to consciousness of briefly presented visual events is modulated by transcranial direct current stimulation of left dorsolateral prefrontal cortex. Sci Rep 2019; 9:10950. [PMID: 31358875 PMCID: PMC6662720 DOI: 10.1038/s41598-019-47527-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/18/2019] [Indexed: 11/12/2022] Open
Abstract
Adaptive behaviour requires the ability to process goal-relevant events at the expense of irrelevant ones. However, perception of a relevant visual event can transiently preclude access to consciousness of subsequent events — a phenomenon called attentional blink (AB). Here we investigated involvement of the left dorsolateral prefrontal cortex (DLPFC) in conscious access, by using transcranial direct current stimulation (tDCS) to potentiate or reduce neural excitability in the context of an AB task. In a sham-controlled experimental design, we applied between groups anodal or cathodal tDCS over the left DLPFC, and examined whether this stimulation modulated the proportion of stimuli that were consciously reported during the AB period. We found that tDCS over the left DLPFC affected the proportion of consciously perceived target stimuli. Moreover, anodal and cathodal tDCS had opposing effects, and exhibited different temporal patterns. Anodal stimulation attenuated the AB, enhancing conscious report earlier in the AB period. Cathodal stimulation accentuated the AB, reducing conscious report later in the AB period. These findings support the notion that the DLPFC plays a role in facilitating information transition from the unconscious to the conscious stage of processing.
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16
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Ramos AA, Hamdan AC, Machado L. A meta-analysis on verbal working memory in children and adolescents with ADHD. Clin Neuropsychol 2019; 34:873-898. [PMID: 31007130 DOI: 10.1080/13854046.2019.1604998] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Objective: Previous meta-analyses have demonstrated verbal working memory (WM) dysfunction in children and adolescents with attention deficit/hyperactivity disorder (ADHD); however, the findings are inconsistent. The main objective of this meta-analysis was to investigate the performance of children and adolescents with ADHD in the Digit Span Backwards (DSB) subtest from the Wechsler Intelligence Scale for Children or Wechsler Adult Intelligence Scale. We also sought to provide an updated meta-analysis on WM in children and adolescents with ADHD.Method: PubMed, PsyINFO, Scopus, and Web of Science were searched to locate studies published between 1990 and 2016 that report DSB scores both of children and adolescents with ADHD and matched controls. Potential moderator variables were also analyzed.Results: Forty-nine studies comparing children and adolescents with ADHD (n = 4956) against healthy controls (n = 3249) generated a medium-sized effect (Hedges' g) of 0.56 (95% CI [0.49, 0.64]), indicating poorer verbal WM performance in those with ADHD. A subgroup meta-analysis of studies with participants aged 8-16 years only demonstrated low heterogeneity (I2 = 17.06, cf. 55.50 for the main analysis). Moreover, the meta-regression showed a negative association (β = -.05, p = .02) between DSB performance differences and increasing age, indicating that for every one year increase in age the effect size decreased by .05.Conclusion: These results, which emanated from the largest meta-analysis concerning verbal WM in ADHD reported to date, reinforce WM as a key domain of cognitive dysfunction in ADHD, and point to age as the main variable influencing DSB performance difficulties.
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Affiliation(s)
- Ari Alex Ramos
- Department of Psychology, Federal University of Paraná, Curitiba, Brazil.,Department of Psychology, University of Otago, Dunedin, New Zealand
| | | | - Liana Machado
- Department of Psychology, University of Otago, Dunedin, New Zealand
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17
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Chen PL, Stenling A, Machado L. Evidence Transcranial Direct Current Stimulation Can Improve Saccadic Eye Movement Control in Older Adults. Vision (Basel) 2018; 2:E42. [PMID: 31735905 PMCID: PMC6835567 DOI: 10.3390/vision2040042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/23/2018] [Accepted: 11/29/2018] [Indexed: 11/16/2022] Open
Abstract
Objectives: Ageing is associated with declines in voluntary eye movement control, which negatively impact the performance of daily activities. Therapies treating saccadic eye movement control deficits are currently lacking. To address the need for an effective therapy to treat age-related deficits in saccadic eye movement control, the current study investigated whether saccadic behaviour in older adults can be improved by anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex using a montage that has been proven to be effective at improving nonoculomotor control functions. Method: The tDCS protocol entailed a 5 cm × 7 cm anodal electrode and an encephalic cathodal reference electrode positioned over the contralateral supraorbital area. In two experiments, healthy older men completed one active (1.5 mA current for 10 min) and one sham stimulation session, with the session order counterbalanced across participants, and eye movement testing following stimulation. In the first experiment, participants rested during the tDCS (offline), whereas in the follow-up experiment, participants engaged in antisaccades during the tDCS (online). Results: Analyses revealed improvements in saccadic performance following active anodal tDCS relative to sham stimulation in the online experiment, but not in the offline experiment, which was presumably due to the activation of the relevant networks during tDCS promoting more targeted effects. Discussion: These outcomes converge with findings pertaining to nonoculomotor cognitive functions, and provide evidence that tDCS can improve saccadic eye movement control in older adults.
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Affiliation(s)
- Po Ling Chen
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin 9054, New Zealand
- Brain Research New Zealand, Auckland 1142, New Zealand
| | - Andreas Stenling
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin 9054, New Zealand
- Brain Research New Zealand, Auckland 1142, New Zealand
- Department of Psychology, Umeå University, 901 87 Umeå, Sweden
- Department of Psychology, University of Gothenburg, SE405 30 Gothenburg, Sweden
| | - Liana Machado
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin 9054, New Zealand
- Brain Research New Zealand, Auckland 1142, New Zealand
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18
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White N, Flannery L, McClintock A, Machado L. Repeated computerized cognitive testing: Performance shifts and test–retest reliability in healthy older adults. J Clin Exp Neuropsychol 2018; 41:179-191. [DOI: 10.1080/13803395.2018.1526888] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Naomi White
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand, Dunedin, New Zealand
| | - Larnee Flannery
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Alice McClintock
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Liana Machado
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand, Dunedin, New Zealand
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