Hemispheric Asymmetry of Supplementary Motor Area Proper: A Functional Connectivity Study of the Motor Network

Motor Control ◽  
2016 ◽  
Vol 20 (1) ◽  
pp. 33-49 ◽  
Author(s):  
Mickael Dinomais ◽  
Eva Chinier ◽  
Isabelle Richard ◽  
Emmanuel Ricalens ◽  
Christophe Aubé ◽  
...  

Cerebral asymmetry is a common feature of human functions. However, there are discrepancies in the literature about functional hemispheric asymmetries in the supplementary motor area (SMA), specifically in the posterior part (SMA-proper). We used resting state functional connectivity MRI to investigate the left-right asymmetries of the functional networks associated with primary motor cortex (M1) and SMA-proper using a “seed”-based correlation analysis in 30 healthy right-handed subjects. We showed that left M1 was more connected with areas involved in the motor system than right M1, and that right SMA-proper had more functional connections than its left counterpart. Our results are in agreement with a leftward asymmetry for M1 connectivity, whereas there is a rightward asymmetry of the SMA-proper connectivity.

2021 ◽  
Author(s):  
Timothy P. Morris ◽  
Aaron Kucyi ◽  
Sheeba Arnold Anteraper ◽  
Maiya Rachel Geddes ◽  
Alfonso Nieto-Castañon ◽  
...  

AbstractInformation about a person’s available energy resources is integrated in daily behavioral choices that weigh motor costs against expected rewards. It has been posited that humans have an innate attraction towards effort minimization and that executive control is required to overcome this prepotent disposition. With sedentary behaviors increasing at the cost of millions of dollars spent in health care and productivity losses due to physical inactivity-related deaths, understanding the predictors of sedentary behaviors will improve future intervention development and precision medicine approaches. In 64 healthy older adults participating in a 6-month aerobic exercise intervention, we use neuroimaging (resting state functional connectivity), baseline measures of executive function and accelerometer measures of time spent sedentary to predict future changes in objectively measured time spent sedentary in daily life. Using cross-validation and bootstrap resampling, our results demonstrate that functional connectivity between 1) the anterior cingulate cortex and the supplementary motor area and 2) the right anterior insula and the left temporoparietal/temporooccipital junction, predict changes in time spent sedentary, whereas baseline cognitive, behavioral and demographic measures do not. Previous research has shown activation in and between the anterior cingulate and supplementary motor area as well as in the right anterior insula during effort avoidance and tasks that integrate motor costs and reward benefits in effort-based decision making. Our results add important knowledge toward understanding mechanistic associations underlying complex sedentary behaviors.


2012 ◽  
Vol 108 (8) ◽  
pp. 2242-2263 ◽  
Author(s):  
Eun Young Choi ◽  
B. T. Thomas Yeo ◽  
Randy L. Buckner

The striatum is connected to the cerebral cortex through multiple anatomical loops that process sensory, limbic, and heteromodal information. Tract-tracing studies in the monkey reveal that these corticostriatal connections form stereotyped patterns in the striatum. Here the organization of the striatum was explored in the human with resting-state functional connectivity MRI (fcMRI). Data from 1,000 subjects were registered with nonlinear deformation of the striatum in combination with surface-based alignment of the cerebral cortex. fcMRI maps derived from seed regions placed in the foot and tongue representations of the motor cortex yielded the expected inverted somatotopy in the putamen. fcMRI maps derived from the supplementary motor area were located medially to the primary motor representation, also consistent with anatomical studies. The topography of the complete striatum was estimated and replicated by assigning each voxel in the striatum to its most strongly correlated cortical network in two independent groups of 500 subjects. The results revealed at least five cortical zones in the striatum linked to sensorimotor, premotor, limbic, and two association networks with a topography globally consistent with monkey anatomical studies. The majority of the human striatum was coupled to cortical association networks. Examining these association networks further revealed details that fractionated the five major networks. The resulting estimates of striatal organization provide a reference for exploring how the striatum contributes to processing motor, limbic, and heteromodal information through multiple large-scale corticostriatal circuits.


Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Veena A Nair ◽  
Brittany M Young ◽  
Zack Nigogosyan ◽  
Alex Remsick ◽  
Sonya Weber ◽  
...  

Introduction: Brain-computer interface (BCI)-EEG is a promising intervention for improving motor function after stroke. However, brain changes following intervention on a BCI-EEG system are not yet fully understood. We examined changes in resting state functional connectivity (RSFC) MRI in the motor network defined by 6 key regions in the left and right primary motor cortex (M1), left and right supplementary motor area (SMA), and left and right premotor cortex (PMC). Additionally, we investigated brain-behavior correlation between rsFC and a battery of outcome measures including the Barthel Index (BI), the Stroke Impact Scale(SIS), and the Action Research Arm Test (ARAT). Methods: Fifteen stroke patients with persistent mild to severe upper extremity impairment following ischemic stroke received intervention using BCI-EEG and were tested before (T1) and at 2-3 weeks (T2) mid intervention. 11 of these patients were also tested a third time at 4-6 weeks at the end of intervention (T3). Eyes closed, 10 minute resting fMRI and anatomical scans were acquired on a GE 3T MRI scanner. Right hemisphere stroke patients’ scans were flipped so that as a group the lesion was in the left (L) hemisphere and the impaired limb right (R). Seed region based connectivity analyses were performed to examine changes in RSFC over time and in inter-hemispheric and intra-hemispheric connectivity, and correlations between brain changes and behavioral changes were investigated. Results: BCI-EEG intervention led to significant increase in intra-hemispheric connectivity (p = .03) from T1 to T3. Inter-hemispheric connectivity increased from T1 to T3, trending towards significance (p = .06). Significant positive correlations were observed between changes in RSFC (L.M1 and L.PMC, L.M1 and R.PMC, L.SMA and R.PMC, and R.PMC and R.SMA) and change in upper extremity BI score (p ranging from .01 to .001); changes in RSFC between L.PMC and R.PMC correlated with hand strength on the SIS (p = .03). A trend was observed between increase in RSFC (L.M1 and R.PMC) and increase in total ARAT score but this was not significant. Conclusions: Results suggest that BCI-EEG intervention facilitate changes in RSFC in the motor network in stroke patients and these changes are associated with improved outcomes.


Stroke ◽  
2021 ◽  
Author(s):  
Robert Schulz ◽  
Marlene Bönstrup ◽  
Stephanie Guder ◽  
Jingchun Liu ◽  
Benedikt Frey ◽  
...  

Background and Purpose: Cortical beta oscillations are reported to serve as robust measures of the integrity of the human motor system. Their alterations after stroke, such as reduced movement-related beta desynchronization in the primary motor cortex, have been repeatedly related to the level of impairment. However, there is only little data whether such measures of brain function might directly relate to structural brain changes after stroke. Methods: This multimodal study investigated 18 well-recovered patients with stroke (mean age 65 years, 12 males) by means of task-related EEG and diffusion-weighted structural MRI 3 months after stroke. Beta power at rest and movement-related beta desynchronization was assessed in 3 key motor areas of the ipsilesional hemisphere that are the primary motor cortex (M1), the ventral premotor area and the supplementary motor area. Template trajectories of corticospinal tracts (CST) originating from M1, premotor cortex, and supplementary motor area were used to quantify the microstructural state of CST subcomponents. Linear mixed-effects analyses were used to relate tract-related mean fractional anisotropy to EEG measures. Results: In the present cohort, we detected statistically significant reductions in ipsilesional CST fractional anisotropy but no alterations in EEG measures when compared with healthy controls. However, in patients with stroke, there was a significant association between both beta power at rest ( P =0.002) and movement-related beta desynchronization ( P =0.003) in M1 and fractional anisotropy of the CST specifically originating from M1. Similar structure-function relationships were neither evident for ventral premotor area and supplementary motor area, particularly with respect to their CST subcomponents originating from premotor cortex and supplementary motor area, in patients with stroke nor in controls. Conclusions: These data suggest there might be a link connecting microstructure of the CST originating from M1 pyramidal neurons and beta oscillatory activity, measures which have already been related to motor impairment in patients with stroke by previous reports.


2021 ◽  
Author(s):  
ATP Jäger ◽  
JM Huntenburg ◽  
SA Tremblay ◽  
U Schneider ◽  
S Grahl ◽  
...  

AbstractIn motor learning, sequence-specificity, i.e. the learning of specific sequential associations, has predominantly been studied using task-based fMRI paradigms. However, offline changes in resting state functional connectivity after sequence-specific motor learning are less well understood. Previous research has established that plastic changes following motor learning can be divided into stages including fast learning, slow learning and retention. A description of how resting state functional connectivity after sequence-specific motor sequence learning (MSL) develops across these stages is missing. This study aimed to identify plastic alterations in whole-brain functional connectivity after learning a complex motor sequence by contrasting an active group who learned a complex sequence with a control group who performed a control task matched for motor execution. Resting state fMRI and behavioural performance were collected in both groups over the course of 5 consecutive training days and at follow-up after 12 days to encompass fast learning, slow learning, overall learning and retention. Between-group interaction analyses showed sequence-specific increases in functional connectivity during fast learning in the sensorimotor territory of the internal segment of right globus pallidus (GPi), and sequence-specific decreases in right supplementary motor area (SMA) in overall learning. We found that connectivity changes in key regions of the motor network including the superior parietal cortex (SPC) and primary motor cortex (M1) were not a result of sequence-specific learning but were instead linked to motor execution. Our study confirms the sequence-specific role of SMA and GPi that has previously been identified in online task-based learning studies in humans and primates, and extends it to resting state network changes after sequence-specific MSL. Finally, our results shed light on a timing-specific plasticity mechanism between GPi and SMA following MSL.


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