Multimodal functional imaging of motor imagery using a novel paradigm

Abstract

Neuroimaging studies have shown that the neural mechanisms of motor imagery (MI) overlap substantially with the mechanisms of motor execution (ME). Surprisingly, however, the role of several regions of the motor circuitry in MI remains controversial, a variability that may be due to differences in neuroimaging techniques, MI training, instruction types, or tasks used to evoke MI. The objectives of this study were twofold: (i) to design a novel task that reliably invokes MI, provides a reliable behavioral measure of MI performance, and is transferable across imaging modalities; and (ii) to measure the common and differential activations for MI and ME with functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG). We present a task in which it is difficult to give accurate responses without the use of either motor execution or motor imagery. The behavioral results demonstrate that participants performed similarly on the task when they imagined vs. executed movements and this performance did not change over time. The fMRI results show a spatial overlap of MI and ME in a number of motor and premotor areas, sensory cortices, cerebellum, inferior frontal gyrus, and ventrolateral thalamus. MI uniquely engaged bilateral occipital areas, left parahippocampus, and other temporal and frontal areas, whereas ME yielded unique activity in motor and sensory areas, cerebellum, precuneus, and putamen. The MEG results show a robust event-related beta band desynchronization in the proximity of primary motor and premotor cortices during both ME and MI. Together, these results further elucidate the neural circuitry of MI and show that our task robustly and reliably invokes motor imagery, and thus may prove useful for interrogating the functional status of the motor circuitry in patients with motor disorders.

Neuroplasticity of imagined wrist actions after spinal cord injury: a pilot study

“…One SCI participant presented increased movement times variance associated with an increased number of MI sources during the posttest. SAM synthetic aperture magnetometry sources, and ERD features of MI yielded by the time-frequency analysis were highly congruent with previous MEG reports in both HC and SCI subjects (Burianova et al 2013;Di Rienzo et al 2013). The sources of ERD were primarily located within the sensorimotor and associative regions of the cortex in both groups (Fig.…”

Cortical beta oscillations and motor thresholds differ across the spectrum of post-stroke motor impairment, a preliminary MEG and TMS study

“…Guided motor imagery (Burianova et al, 2013; or passive somatosensory stimuli (Jamali et al, 2014) may overcome this barrier in future studies.…”

“…In the healthy brain, a robust spatiotemporal pattern of beta ERD/ERS has been characterised for simple voluntary movements (Pfurtscheller and Lopes da Silva, 1999), passive movements (Keinrath et al, 2006) and motor imagery (Burianova et al, 2013;Pfurtscheller et al, 2005). Changes to beta-band activity can occur with healthy ageing (Rossiter et al, 2014c) and sensorimotor disorders including stroke (Rossiter et al, 2014b), Parkinson's disease (HeinrichsGraham et al, 2014;Jenkinson and Brown, 2011) and amyotrophic lateral sclerosis (Bizovicar et al, 2014;Kasahara et al, 2012), suggesting an association between altered beta oscillations and sensorimotor pathology.…”

Understanding bimanual coordination across small time scales from an electrophysiological perspective

“…In particular, this strategy has not been fully exploited in the area of motor research. Some studies have started to implement this strategy with motor imagery tasks (Burianová et al, 2013;Formaggio et al, 2010). Given the particular strengths of each method, multimodal approaches might also help to interconnect different levels that have been studied separately or only by pairwise combinations so far: structure (brain grey and white matter), function (brain activity), and connectivity.…”