Intervention-induced changes in neural connectivity during motor preparation may affect cortical activity at motor execution

Abstract

possibility, different types of nonlinear coupling have been found to arise during motor tasks/regions in both healthy and disease 15,16. Following a stroke, spatial and frequency features during motor preparation have been shown to be altered. For example, previous studies have reported overactivation of the supplementary motor area (SMA) 17 as well as increased overlap of limb representations on the cortex 18 , which is especially pronounced in individuals with severe impairments. Post-stroke individuals also display stroke-induced changes in these neuronal oscillations during movement such as reduced beta desynchronization and changes in gamma-beta coupling between sensorimotor regions 19,20. Following interventions, changes occur not only at motor performance level but also in motor related brain activity. The majority of intervention studies to date have focused on cortical changes related to motor execution. We argue that understanding how changes in motor preparation may facilitate changes in motor execution is also critical. One piece of the evidence in favor of this is from Norman and colleagues, who showed that specifically training preparation-related cortical oscillations led to subsequent improvements in motor function, further cementing the crucial role for motor preparation in proper movement 21. Given the critical role of motor preparation in performance, investigating how these frequency characteristics during motor preparation change following an intervention would provide additional details into the nature of any observed cortical reorganization. An important caveat regarding motor preparation and execution is that it may differ based on the type of movement performed. For instance, even healthy controls show differences in motor preparation as additional joints need to be controlled for a movement 9. This is particularly relevant in stroke since hand opening ability and reaching performance are exacerbated when combined with having to simultaneously lift at the shoulder, and these behavioral deficits are accompanied by abnormal changes in cortical activity during both motor preparation and execution. Whether an intervention can positively change cortical activity in motor preparation and execution across these different types of movements is still unclear. This study was designed to examine how cortical changes in motor preparation may accompany changes in motor execution following an intervention that targeted hand/arm function recovery in individuals with severe chronic hemiparetic stroke. We hypothesized that intervention-induced changes in cortico-cortico interactions during motor preparation would complement changes in activity at motor execution specifically towards an increased reliance on the ipsilesional hemisphere. To test this hypothesis, we examined dynamic cortical coupling between motor regions during motor preparation and cortical activity within motor regions at motor execution for hand opening in isolation and combined with lifting at the shoulder following an effective device...

Brain Function and Upper Limb Deficit in Stroke With Motor Execution and Imagery: A Cross-Sectional Functional Magnetic Resonance Imaging Study

“…As found in our motor execution task with the affected limb, the activation of the ipsilateral M1 and SMA showed obvious changes, consistent with previous studies where they played an important role in mediating motor preparation and execution ( Pan et al, 2019 ; Cuenca-Martínez et al, 2020 ). Effective interventions have demonstrated the ability to improve motor function by re-engaging ipsilesional resources, which appears to be critical and feasible for hand function recovery even in individuals with severe chronic stroke ( Wilkins et al, 2020 ).…”

Virtual Reality Assisted Motor Imagery for Early Post-Stroke Recovery: A Review

“…MI in rehabilitation aims to teach patients ways to promote reorganisation of the lesion areas by recruiting undamaged neurons and enhancing brain activity in other neuronal loops [26], [27]. Stroke patients with serious motor impairments are not capable to participate in conventional physiotherapy and occupational therapy due to severely paretic limbs, but stroke patients can activate their motor brain areas by MI even when they are physically inactive [15], [16], [30].…”

“…MI is the ability to mentally perform a movement without moving the body [24], [25]. MI in rehabilitation aids to promote reorganisation of the lesioned brain areas by recruiting undamaged neurons and enhancing brain activity in other neuronal networks [26], [27]. MI abilities of stroke patients may be impaired initially, but this ability can be recovered in the first weeks of stroke onset [28].…”

Alpha, Beta, and Gamma Oscillations in Cortical Communication During Motor Preparation

“…Table 2 Twelve network models with connections between these 5 sources were created (detailed model structures can be seen in our previous publication 3 ), which have successfully been used before in similar motor tasks for our previous studies in non-disabled controls 3,40 and stroke patients 40 . These 12 models were separated into 2 groups.…”