Using Motor Imagery to Study the Neural Substrates of Dynamic Balance

Abstract

This study examines the cerebral structures involved in dynamic balance using a motor imagery (MI) protocol. We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined swaying on a balance board along the sagittal plane to point a laser at target pairs of different sizes (small, large). We used a matched visual imagery (VI) control task and recorded imagery durations during scanning. MI and VI durations were differentially influenced by the sway accuracy requirement, indicating that MI of balance is sensitive to the increased motor control necessary to point at a smaller target. Compared to VI, MI of dynamic balance recruited additional cortical and subcortical portions of the motor system, including frontal cortex, basal ganglia, cerebellum and mesencephalic locomotor region, the latter showing increased effective connectivity with the supplementary motor area. The regions involved in MI of dynamic balance were spatially distinct but contiguous to those involved in MI of gait (Bakker et al., 2008; Snijders et al., 2011; Crémers et al., 2012), in a pattern consistent with existing somatotopic maps of the trunk (for balance) and legs (for gait). These findings validate a novel, quantitative approach for studying the neural control of balance in humans. This approach extends previous reports on MI of static stance (Jahn et al., 2004, 2008), and opens the way for studying gait and balance impairments in patients with neurodegenerative disorders.

Body Sway Increases After Functional Inactivation of the Cerebellar Vermis by cTBS

“…In this line, the relatively long latency from the visual shift to the earliest changes in sway suggests the possibility that the process of visual integration for balance stabilization occurs at cortical level, since the cortex is certainly involved in controlling critical postures [75–82]. …”

Regional volumes in brain stem and cerebellum are associated with postural impairments in young brain‐injured patients

“…The role of the midbrain in balance control is confirmed by studies using functional MRI and positron emission tomography, which have shown that the execution or motor imagery of postural tasks does not only activate cortical regions in the cerebellum and cerebrum, but also the midbrain [Ferraye et al, 2014;Ouchi et al, 1999]. It has been suggested that the midbrain is part of a network involving the cerebellum, frontal areas and thalamus working interactively to control dynamic balance [Ferraye et al, 2014].…”

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