scholarly journals Age-related differences in the role of the prefrontal cortex in sensory-motor training gains: A tDCS study

2020 ◽  
Author(s):  
Si Jing Tan ◽  
Hannah L. Filmer ◽  
Paul E. Dux
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Prefrontal Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Response Selection ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Direct Current Stimulation ◽  
Age Related

AbstractThe ability to process multiple sources of information concurrently is particularly impaired as individuals age and such age-related increases in multitasking costs have been linked to impairments in response selection. Previous neuroimaging studies with young adults have implicated the left hemisphere prefrontal cortex (PFC) as a key neural substrate of response selection. In addition, several transcranial direct current stimulation studies (tDCS) have provided causal evidence implicating this region in response selection and multitasking operations. For example, Filmer at al. (2013b) demonstrated that typically observed response selection learning/training gains in young adults were disrupted via offline transcranial direct current stimulation (tDCS) of left, but not right, PFC. Here, considering evidence of functional dedifferentiation in the brains of older adults, we assessed if this pattern of response selection learning disruption via tDCS to the left PFC is observed in older adults, testing if this region remains a key response selection node as individuals age. In a pre-registered study with 58 older adults, we applied anodal, cathodal, and sham stimulation to left and right PFC, and measured performance as participants trained on low- and high-response selection load tasks. Active stimulation did not disrupt training in older adults as compared to younger adults. However, there was evidence of enhanced training gains via tDCS, which scaled with response selection task difficulty. The results highlight age-related differences in the casual neural substrates that subserve response selection and learning.

scholarly journals Evidence Transcranial Direct Current Stimulation Can Improve Saccadic Eye Movement Control in Older Adults

Vision ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 42 ◽  
Author(s):  
Po Chen ◽  
Andreas Stenling ◽  
Liana Machado
Keyword(s):  
Older Adults ◽  
Eye Movement ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Movement Control ◽  
Saccadic Eye Movement ◽  
Eye Movement Control ◽  
Sham Stimulation ◽  
Direct Current Stimulation ◽  
Age Related

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.

scholarly journals Age-Related Decline in Pragmatic Reasoning of Older Adults

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 703-704
Author(s):  
W Quin Yow ◽  
Jia Wen Lee ◽  
Xiaoqian Li
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Contextual Information ◽  
The Novel ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Age Related ◽  
Visible Object ◽  
Novel Objects ◽  
Pragmatic Reasoning

Abstract As speech is often ambiguous, pragmatic reasoning—the process of integrating multiple sources of information including semantics, ostensive cues and contextual information (Bohn & Frank, 2019)—is essential to understanding a speaker’s intentions. Despite current literature suggesting that certain social cognitive processes such as gaze-processing (Slessor et al., 2014) appear to be impaired in late adulthood, it is not well understood if pragmatic reasoning decline with age. Here, we examined young adults’ (aged 19-25; n=41) and older adults’ (aged 60-79; n=41) ability to engage in pragmatic reasoning in a cue integration task. In Experiment 1, participants had to integrate contextual (participants and speaker knew there were two novel objects but the latter could only see one), semantic (“There’s the [novel-label]” or “Where’s the [novel-label]”), and gaze (speaker looked at the mutually-visible object) cues to identify the referent (Nurmsoo & Bloom, 2008). In Experiment 2, participants received contextual and semantic cues less gaze cue. In both experiments, the target referent object for “There” and “Where” trials was the mutually-visible object and the object the speaker could not see respectively. Overall, young adults outperformed older adults, even in the simpler two-cue Experiment 2 (ps<.006). While older adults were significantly above chance in “There” trials for both experiments as well as “Where” trials in Experiment 2 (ps<.05), they had specific difficulty in integrating three cues in “Where” trials, where a more sophisticated interpretation of the multiple cues was required (p=.42). Our findings provide important insights into an age-related decline of pragmatic reasoning in older adults.

scholarly journals Transcranial Direct Current Stimulation May Improve Cognitive-Motor Function in Functionally Limited Older Adults

2018 ◽  
Vol 32 (9) ◽  
pp. 788-798 ◽  
Author(s):  
Brad Manor ◽  
Junhong Zhou ◽  
Rachel Harrison ◽  
On-Yee Lo ◽  
Thomas G. Travison ◽  
...  
Keyword(s):  
Older Adults ◽  
Prefrontal Cortex ◽  
Executive Function ◽  
Direct Current ◽  
Dual Task ◽  
Transcranial Direct Current Stimulation ◽  
Dorsolateral Prefrontal Cortex ◽  
Dual Tasking ◽  
Direct Current Stimulation ◽  
Dorsolateral Prefrontal

Objective. To determine the effects of a transcranial direct current stimulation (tDCS) intervention with the anode placed over the left dorsolateral prefrontal cortex (dlPFC) and cathode over the right supraorbital region, on cognition, mobility, and “dual-task” standing and walking in older adults with mild-to-moderate motor and cognitive impairments. Methods. A double-blinded, block-randomized, sham-controlled trial was conducted in 18 nondemented, ambulatory adults aged ⩾65 years with slow walking speed (⩽1.0 m/s) and “executive” dysfunction (Trail Making Test B score ⩽25th percentile of age- and education-matched norms). Interventions included ten 20-minute sessions of tDCS or sham stimulation. Cognition, mobility, and dual-task standing and walking were assessed at baseline, postintervention, and 2 weeks thereafter. Dual tasking was also assessed immediately before and after the first tDCS session. Results. Intervention compliance was high (mean ± SD = 9.5 ± 1.1 sessions) and no unexpected or serious side effects were reported. tDCS, compared with sham, induced improvements in the Montreal Cognitive Assessment total score ( P = .03) and specifically within the executive function subscore of this test ( P = .002), and in several metrics of dual-task standing and walking ( P < .05). Each of these effects persisted for 2 weeks. tDCS had no effect on the Timed Up-and-Go test of mobility or the Geriatric Depression Scale. Those participants who exhibited larger improvements in dual-task standing posture following the first tDCS session exhibited larger cognitive-motor improvements following 2 weeks of tDCS ( P < .04). Interpretation. tDCS intervention designed to stimulate the left dorsolateral prefrontal cortex may improve executive function and dual tasking in older adults with functional limitations.

Modulation of Adaptive Cognitive Control by Prefrontal High-Definition Transcranial Direct Current Stimulation in Older Adults

2019 ◽  
Vol 74 (7) ◽  
pp. 1174-1183 ◽  
Author(s):  
Oyetunde Gbadeyan ◽  
Marco Steinhauser ◽  
Alexander Hunold ◽  
Andrew K Martin ◽  
Jens Haueisen ◽  
...  
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Control ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Error Rates ◽  
Advanced Age ◽  
Induced Current ◽  
High Definition ◽  
Direct Current Stimulation

Abstract Objective Adaptive cognitive control frequently declines in advanced age. Because high-definition transcranial direct current stimulation (HD-tDCS) of the right dorsolateral prefrontal cortex (DLPFC) improved cognitive control in young adults, we investigated if this montage can also improve cognitive control in older individuals. Method In a double-blind, sham HD-tDCS controlled, cross-over design, 36 older participants received right DLPFC HD-tDCS during a visual flanker task. Conflict adaptation (CA) effects on response time (RT) and error rates (ER) assessed adaptive cognitive control. Biophysical modeling assessed the magnitude and distribution of induced current in older adults. Results Active HD-tDCS enhanced CA in older adults. However, this positive behavioral effect was limited to CA in ER. Similar to results obtained in healthy young adults, current modeling analysis demonstrated focal current delivery to the DLPFC with sufficient magnitude of the induced current to modulate neural function in older adults. Discussion This study confirms the effectiveness of HD-tDCS to modulate adaptive cognitive control in advanced age.

scholarly journals Transcranial Direct Current Stimulation Enhances Episodic Memory in Healthy Older Adults by Modulating Retrieval-Specific Activation

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Lijuan Huo ◽  
Zhiwei Zheng ◽  
Jia Huang ◽  
Rui Li ◽  
Jin Li ◽  
...  
Keyword(s):  
Older Adults ◽  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Anterior Cingulate ◽  
Controlled Study ◽  
Healthy Older Adults ◽  
Sham Stimulation ◽  
Direct Current Stimulation

Memory decline has become an issue of major importance in the aging society. Anodal transcranial direct current stimulation (atDCS) is a viable tool to counteract age-associated episodic memory deterioration. However, the underlying neural mechanisms are unclear. In this single-blind, sham-controlled study, we combined atDCS and functional magnetic resonance imaging to assess the behavioral and neural consequences of multiple-session atDCS in older adults. Forty-nine healthy older adults received either 10 sessions of anodal or sham stimulation over the left dorsolateral prefrontal cortex. Before and after stimulation, participants performed a source memory task in the MRI scanner. Compared to sham stimulation, atDCS significantly improved item memory performance. Additionally, atDCS significantly increased regional brain activity around the stimulation area in the prefrontal cortex and extended to the bilateral anterior cingulate cortex. Neural changes in the prefrontal cortex correlated with memory gains. Our findings therefore indicate that multiple-session offline atDCS may improve memory in older adults by inducing neural alterations.

Prefrontal Modulation of Visual Processing and Sustained Attention in Aging, a tDCS–EEG Coregistration Approach

2018 ◽  
Vol 30 (11) ◽  
pp. 1630-1645 ◽  
Author(s):  
Méadhbh B. Brosnan ◽  
Mahnaz Arvaneh ◽  
Siobhán Harty ◽  
Tara Maguire ◽  
Redmond O'Connell ◽  
...  
Keyword(s):  
Older Adults ◽  
Direct Current ◽  
Sustained Attention ◽  
Transcranial Direct Current Stimulation ◽  
Visual Processing ◽  
Cortical Excitability ◽  
Attentional Focus ◽  
Direct Current Stimulation ◽  
Age Related ◽  
The Right

The ability to sustain attention is integral to healthy cognition in aging. The right PFC (rPFC) is critical for maintaining high levels of attentional focus. Whether plasticity of this region can be harnessed to support sustained attention in older adults is unknown. We used transcranial direct current stimulation to increase cortical excitability of the rPFC, while monitoring behavioral and electrophysiological markers of sustained attention in older adults with suboptimal sustained attention capacity. During rPFC transcranial direct current stimulation, fewer lapses of attention occurred and electroencephalography signals of frontal engagement and early visual attention were enhanced. To further verify these results, we repeated the experiment in an independent cohort of cognitively typical older adults using a different sustained attention paradigm. Again, prefrontal stimulation was associated with fewer attentional lapses. These experiments suggest the rPFC can be manipulated in later years to increase top–down modulation over early sensory processing and improve sustained attention performance. This holds valuable information for the development of neurorehabilitation protocols to ameliorate age-related deficits in this capacity.

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