Motor neuroplasticity: A MEG-fMRI study of motor imagery and execution in healthy ageing. (September 2020)

• Record Type: Journal Article
• Authors: Burianová, Hana; Marstaller, Lars; Rich, Anina N.; Williams, Mark A.; Savage, Greg; Ryan, Margaret; Sowman, Paul F.
• Is Part Of: Neuropsychologia. Volume 146(2020)
• Publication Date: 2020-09
• Subjects: Ageing -- Compensation -- Dedifferentiation -- Motor execution -- Motor imagery; Neuropsychology -- Periodicals; Neurology -- Periodicals; Psychophysiology -- Periodicals; Neuropsychologie -- Périodiques; Neuropsychology; Periodicals; Electronic journals; 616.8
• DOI: 10.1016/j.neuropsychologia.2020.107539
• Languages: English
• ISSNs: 0028-3932

Abstract

Abstract: Age-related decline in motor function is associated with over-activation of the sensorimotor circuitry. Using a multimodal MEG-fMRI paradigm, we investigated whether this neural over-recruitment in old age would be related to changes in movement-related beta desynchronization (MRBD), a correlate of the inhibitory neurotransmitter γ-aminobutyric acid (GABA), and whether it would characterize compensatory recruitment or a reduction in neural specialization (dedifferentiation). We used MEG to assess age-related changes in beta band oscillations in primary motor cortices, fMRI to localize age-related changes in brain activity, and the Finger Configuration Task to measure task performance during overt and covert motor processing: motor execution (ME) and motor imagery (MI). The results are threefold: first, showing age-related neuroplasticity during ME of older adults, compared to young adults, as evidenced by increased MRBD in motor cortices and over-recruitment of sensorimotor areas; second, showing similar age-related neuroplastic changes during MI; and finally, showing signs of dedifferentiation during ME in older adults whose performance negatively correlated with connectivity to bilateral primary motor cortex. Together, these findings demonstrate that elevated MRBD levels, reflecting greater GABAergic inhibitory activity, and over-activation of the sensorimotor network during ME may not be compensatory, but rather might reflect an age-related decline of the quality of the underlying neural signal. Highlights: We examined the underlying mechanism of age-related sensorimotor over-activation. We used a multimodal paradigm and measured motor execution and motor imagery. Old adults showed increased MRBD and over-activation of sensorimotor network. Motor performance of old adults negatively covaried with bilateral M1 connectivity. The findings suggest age-related dedifferentiation within the sensorimotor circuitry.