Exploring and optimizing the neuroplastic effects of anodal transcranial direct current stimulation over the primary motor cortex of older humans
| Autor: | Michael A. Nitsche, Mohsen Mosayebi-Samani, Min-Fang Kuo, Leila Farnad, Ensiyeh Ghasemian-Shirvan |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Aging
medicine.medical_treatment Biophysics Stimulation Neurosciences. Biological psychiatry. Neuropsychiatry Transcranial Direct Current Stimulation 050105 experimental psychology tDCS 03 medical and health sciences 0302 clinical medicine Neuroplasticity medicine Humans 0501 psychology and cognitive sciences Young adult Set (psychology) Aged Aged 80 and over TMS MEP Motor cortex Neuronal Plasticity Transcranial direct-current stimulation business.industry General Neuroscience 05 social sciences Cognition Middle Aged Evoked Potentials Motor Transcranial Magnetic Stimulation medicine.anatomical_structure Cortical Excitability Neurology (clinical) Primary motor cortex business Neuroscience 030217 neurology & neurosurgery RC321-571 |
| Zdroj: | Brain Stimulation, Vol 14, Iss 3, Pp 622-634 (2021) Brain stimulation, 14(3):622-634 |
| Popis: | Background tDCS modulates cortical plasticity and has shown potential to improve cognitive/motor functions in healthy young humans. However, age-related alterations of brain structure and functions might require an adaptation of tDCS-parameters to achieve a targeted plasticity effect in older humans and conclusions obtained from young adults might not be directly transferable to older adults. Thus, our study aimed to systematically explore the association between tDCS-parameters and induced aftereffects on motor cortical excitability to determine optimal stimulation protocols for older individuals, as well as to investigate age-related differences of motor cortex plasticity in two different age groups of older adults. Methods 32 healthy, volunteers from two different age groups of Young-Old (50–65 years, n = 16) and Old-Old (66–80 years, n = 16) participated in this study. Anodal tDCS was applied over the primary motor cortex, with respective combinations of three intensities (1, 2, and 3 mA) and durations (15, 20, and 30 min), in a sham-controlled cross-over design. Cortical excitability alterations were monitored by single-pulse TMS-induced MEPs until the next day morning after stimulation. Results All active stimulation conditions resulted in a significant enhancement of motor cortical excitability in both age groups. The facilitatory aftereffects of anodal tDCS did not significantly differ between age groups. We observed prolonged plasticity in the late-phase range for two protocols with the highest stimulation intensity (i.e., 3 mA-20 min, 3 mA-30 min). Conclusions Our study highlights the role of stimulation dosage in tDCS-induced neuroplastic aftereffects in the motor cortex of healthy older adults and delivers crucial information about optimized tDCS protocols in the domain of the primary motor cortex. Our findings might set the grounds for the development of optimal stimulation protocols to reinstate neuroplasticity in different cortical areas and induce long-lasting, functionally relevant plasticity in normal aging and in pathological conditions, which would require however systematic tDCS titration studies over respective target areas. |
| Databáze: | OpenAIRE |
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