Duration-dependent effects of the BDNF Val66Met polymorphism on anodal tDCS induced motor cortex plasticity in older adults: a group and individual perspective

AbstractSize and duration of the neuroplastic effects of tDCS depend on stimulation parameters, including stimulation duration and intensity of current. The impact of stimulation parameters on physiological effects is partially non-linear. To improve the utility of this intervention, it is critical to gather information about the impact of stimulation duration and intensity on neuroplasticity, while expanding the parameter space to improve efficacy. Anodal tDCS of 1–3 mA current intensity was applied for 15–30 minutes to study motor cortex plasticity. Sixteen healthy right-handed non-smoking volunteers participated in 10 sessions (intensity-duration pairs) of stimulation in a randomized cross-over design. Transcranial magnetic stimulation (TMS)-induced motor-evoked potentials (MEP) were recorded as outcome measures of tDCS effects until next evening after tDCS. All active stimulation conditions enhanced motor cortex excitability within the first 2 hours after stimulation. We observed no significant differences between the three stimulation intensities and durations on cortical excitability. A trend for larger cortical excitability enhancements was however observed for higher current intensities (1 vs 3 mA). These results add information about intensified tDCS protocols and suggest that the impact of anodal tDCS on neuroplasticity is relatively robust with respect to gradual alterations of stimulation intensity, and duration.

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Increasing motor cortex plasticity with spaced paired associative stimulation at different intervals in older adults

European Journal of Neuroscience ◽

10.1111/ejn.13729 ◽

2017 ◽

Vol 46 (11) ◽

pp. 2674-2683 ◽

Cited By ~ 6

Author(s):

Simranjit K. Sidhu ◽

Maryam Pourmajidian ◽

George M. Opie ◽

John G. Semmler

Keyword(s):

Older Adults ◽

Motor Cortex ◽

Paired Associative Stimulation ◽

Motor Cortex Plasticity

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ASSOCIATIONS OF LATER-LIFE EDUCATION, THE BDNF VAL66MET POLYMORPHISM AND COGNITIVE CHANGE IN OLDER ADULTS

Journal of Prevention of Alzheimer's Disease ◽

10.14283/jpad.2019.40 ◽

2019 ◽

pp. 1-6

Author(s):

D.D. Ward ◽

M.J. Summers ◽

M.J. Valenzuela ◽

V.K. Srikanth ◽

J.J. Summers ◽

...

Keyword(s):

Older Adults ◽

Language Processing ◽

Statistical Significance ◽

Later Life ◽

Cognitive Change ◽

Dependent Manner ◽

Val66met Polymorphism ◽

Bdnf Val66met Polymorphism ◽

University Level ◽

Life Education

In 358 participants of the Tasmanian Healthy Brain Project, we quantified the cognitive consequences of engaging in varying loads of university-level education in later life, and investigated whether or not BDNF Val66Met affected outcomes. Assessment of neuropsychological, health, and psychosocial function was undertaken at baseline, 12-month, and 24-month follow-up. Education load was positively associated with change in language processing performance, but this effect did not reach statistical significance (P = 0.064). The BDNF Val66Met polymorphism significantly moderated the extent to which education load was associated with improved language processing (P = 0.026), with education load having a significant positive relationship with cognitive change in BDNF Met carriers but not in BDNF Val homozygotes. In older adults who carry BDNF Met, engaging in university-level education improves language processing performance in a load-dependent manner.

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