The BOLD response in primary motor cortex and supplementary motor area during kinesthetic motor imagery based graded fMRI neurofeedback

Abstract

There is increasing interest in exploring the use of functional MRI neurofeedback (fMRI-NF) as a therapeutic technique for a range of neurological conditions such as stroke and Parkinson's disease (PD). One main therapeutic potential of fMRI-NF is to enhance volitional control of damaged or dysfunctional neural nodes and networks via a closed-loop feedback model using mental imagery as the catalyst of self-regulation. The choice of target node/network and direction of regulation (increase or decrease activity) are central design considerations in fMRI-NF studies. Whilst it remains unclear whether the primary motor cortex (M1) can be activated during motor imagery, the supplementary motor area (SMA) has been robustly activated during motor imagery. Such differences in the regulation potential between primary and supplementary motor cortex are important because these areas can be differentially affected by a stroke or PD, and the choice of fMRI-NF target and grade of self-regulation of activity likely have substantial influence on the clinical effects and cost effectiveness of NF-based interventions. In this study we therefore investigated firstly whether healthy subjects would be able to achieve self-regulation of the hand-representation areas of M1 and the SMA using fMRI-NF training. There was a significant decrease in M1 neural activity during fMRI-NF, whereas SMA neural activity was increased, albeit not with the predicated graded effect. This study has important implications for fMRI-NF protocols that employ motor imagery to modulate activity in specific target regions of the brain and to determine how they may be tailored for neurorehabilitation.

A Guide to Literature Informed Decisions in the Design of Real Time fMRI Neurofeedback Studies: A Systematic Review

“…These tasks typically involve either motor imagery or finger tapping paradigms (e.g., Berman et al, 2012) and involve primarily upregulation of primary motor or premotor/supplementary motor activity (SMA). However, there are mixed results in this field; for example, the previously cited study from Berman and colleagues found that primary motor cortex regulation was possible during finger tapping but not motor imagery, while Mehler et al (2019) found that neurofeedback was associated with a decrease in primary motor but an increase in SMA engagement activity during motor imagery. Rt-fMRI-NF training focusing on upregulating the SMA during finger tapping and motor imagery is promising for reducing motor symptoms of Parkinson's (Subramanian et al, 2016) Huntington's (Papoutsi et al, 2018), and chronic stroke (Liew et al, 2016).…”

Graded fMRI Neurofeedback Training of Motor Imagery in Middle Cerebral Artery Stroke Patients: A Preregistered Proof-of-Concept Study

“…This data exclusion compromises significantly the power of the current study, in particular in combination with a second threshold that discards entire runs if more than 30% of volumes are affected. For comparison, we applied the same threshold (FD > 0.5 mm) to existing head motion data acquired from a previous experiment with a similar fMRI-NF paradigm that was conducted in young healthy participants (Mehler et al, 2019b). We found that only ∼3.4% of volumes showed too large motion (compared to 33% for patients in the present study) and that median head motion ranged from 0.10 to 0.25 mm between participants with a group median of 0.15 mm (compared to 0.17-1.19 mm between patients with a group median of 0.32 mm for the present study).…”

A Multi-Target Motor Imagery Training Using Bimodal EEG-fMRI Neurofeedback: A Pilot Study in Chronic Stroke Patients

“…In particular, while several studies have shown robust SMA activation during kinesthetic motor imagery, it is still unclear whether M1 can be consistently activated. Some motor imagery studies reported significant activation (Sharma et al, 2008), however, fMRI NF studies found non-conclusive results at group level (Chiew et al, 2012;Blefari et al, 2015) and one recent study showed deactivation of M1 during kinesthetic motor imagery-based upregulation training of the SMA and M1 (Mehler et al, 2019). M1 involvement may depend on the subject and the nature of performed motor imagery task and there is no evidence that it is consistently activated, at least in short training protocols (Hétu et al, 2013).…”

“…Besides, the choice of the cortical target of NF training has a critical impact on the rehabilitation outcome. If ipsilesional primary motor cortex (M1) has been suggested to be the most promising target for an efficient motor recovery (Favre et al, 2014), supplementary motor area (SMA) is easier to engage during motor imagery (Sharma et al, 2006;Mehler et al, 2019) than M1 (Berman et al, 2012;Chiew et al, 2012;Blefari et al, 2015) and may play an important role in restoring motor function in more severely affected patients (Di Pino et al, 2014;Plow et al, 2015). In particular, while several studies have shown robust SMA activation during kinesthetic motor imagery, it is still unclear whether M1 can be consistently activated.…”