Baseline sensorimotor GABA levels shape neuroplastic processes induced by motor learning in older adults.
Hum Brain Mapp
; 41(13): 3680-3695, 2020 09.
Article
en En
| MEDLINE
| ID: mdl-32583940
ABSTRACT
Previous research in young adults has demonstrated that both motor learning and transcranial direct current stimulation (tDCS) trigger decreases in the levels of gamma-aminobutyric acid (GABA) in the sensorimotor cortex, and these decreases are linked to greater learning. Less is known about the role of GABA in motor learning in healthy older adults, a knowledge gap that is surprising given the established aging-related reductions in sensorimotor GABA. Here, we examined the effects of motor learning and subsequent tDCS on sensorimotor GABA levels and resting-state functional connectivity in the brains of healthy older participants. Thirty-six older men and women completed a motor sequence learning task before receiving anodal or sham tDCS to the sensorimotor cortex. GABA-edited magnetic resonance spectroscopy of the sensorimotor cortex and resting-state (RS) functional magnetic resonance imaging data were acquired before and after learning/stimulation. At the group level, neither learning nor anodal tDCS significantly modulated GABA levels or RS connectivity among task-relevant regions. However, changes in GABA levels from the baseline to post-learning session were significantly related to motor learning magnitude, age, and baseline GABA. Moreover, the change in functional connectivity between task-relevant regions, including bilateral motor cortices, was correlated with baseline GABA levels. These data collectively indicate that motor learning-related decreases in sensorimotor GABA levels and increases in functional connectivity are limited to those older adults with higher baseline GABA levels and who learn the most. Post-learning tDCS exerted no influence on GABA levels, functional connectivity or the relationships among these variables in older adults.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Aprendizaje Seriado
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Envejecimiento
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Espectroscopía de Resonancia Magnética
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Conectoma
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Corteza Sensoriomotora
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Estimulación Transcraneal de Corriente Directa
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Ácido gamma-Aminobutírico
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Actividad Motora
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Plasticidad Neuronal
Límite:
Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Año:
2020
Tipo del documento:
Article