Functional MRI activation of primary and secondary motor areas in healthy subjects

BACKGROUND： Functional MRI （fMRI） demonstrates the localization of hand representation in the motor cortex, thereby providing feasible noninvasive mapping of functional activities in the human brain. OBJECTIVE： To observe cortical activation within different cortical motor regions during repetitive hand movements in healthy subjects through the use of fMRI. DESIGN： An observational study, with each subject acting as his own control. SETTING： Department of Radiology, the First Affiliated Hospital of Nanchang University. PARTICIPANTS： Seven healthy volunteers, 4 males and 3 females, aged 19 to 38 years, participated in the study. All subjects were right-handed, with no neurological or psychological disorders. Informed written consent was obtained from all subjects, and the study was approved by the Institutional Review Board of the First Affiliated Hospital of Nanchang University. METHODS： The study was performed at the Department of Radiology between June-August 2005. A 1.5 Tesla Siemens MRI scanner （Symphony, Germany） was used to acquire T1-weighted structural images, which were oriented parallel to the line running through the anterior and the posterior commissures. Subjects were instructed on a task and were allowed to practice briefly prior to the imaging procedure. The motor activation task consisted of the right hand performing a clenching movement. The T1-W images were acquired from six alternating epochs of rest and activation from all seven healthy subjects. Data were collected with echoplanar imaging of brain oxygen level dependent （BOLD） sequence. Each series comprised six cycles of task performance （30 seconds）, alternating with rest （30 seconds） periods, and 3-second time intervals. The differences between active and baseline fMRI imaging were calculated using the student t-test. Differential maps were overlaid on the high resolution TI-W structural image for neuroanatomical correlation of activation areas. MAIN OUTCOME MEASURES： The omega-shaped hand knobs were recognized on T1-W structural images. Active signal changes in the primary （M1） and secondary motor （M2） areas, as well as the relationship between the hand knobs and M1 area activation, were analyzed. Region of interest was selected for signal change quantitative graphic analysis. RESULTS： All 7 enrolled volunteers were included in the final analysis. In the present study, hand knob structures were recognized on T1-weighted images in all subjects and were omega-shaped in the axial plane. Significant functional activations were observed in the contralateral primary motor area of all subjects. Activation signals were distributed mainly in the central sulcus around the hand knob. The contralateral primary sensory （S1） cortex was activated in most cases, and ipsilateral M1 was activated in 3 subjects. Contralateral or bilateral supplementary motor area （SMA） was also activated in 6 cases. Premotor area, or super parietal lobe, was activated in two subjects. Three-dimensional reconstruction demonstrated that the active signal of M1 was primarily located at the middle-lateral surface of the contralateral precentral gyrus in Brodman＇s area 4, and the signal of SMA activation was located in the mesial surface of the premotor area. CONCLUSION： The knob structure of the precentral gyrus is the representative motor area for hand movement. The cerebral cortical motor network was extensively activated during voluntary hand movements in normal subjects. In alert, conscious human subjects, the activated fMRI signal safely and non-invasively localized and lateralized the motor cortical activity associated with simple voluntary repetitive hand movements. Whether higher cognitive functions, such as perception and speech, can be similarly mapped using the fMRI technique and the BOLD method remains to be determined in future well-designed human studies.

Analysis of Brain Activation during Motor Imagery Based on fMRI

Brain activation during motor imagery （MI） has been studied extensively for years. Based on studies of brain activations of MI, in present study, a complex finger tapping imagery and execution experi- ment is designed to test the brain activation during MI. The experiment results show that during MI, brain activation exists mainly in the supplementary motor area （SMA） and precentral area where the dorsal premotor area （PMd） and the primary motor area （M1） mainly located; and some activation can be also observed in the primary and secondary somatosensory cortex （S1）, the inferior parietal lobule （IPL） and the superior parietal lobule （SPL）. Additionally, more brain activation can be observed during left-hand MI than during right-hand MI, this difference probably is caused by asymmetry of brain.

Right lower limb apraxia in a patient with left supplementary motor area infarction: intactness of the corticospinal tract confirmed by transcranial magnetic stimulation

We reported a 50-year-old female patient with left supplementary motor area infarction who presented right lower limb apraxia and investigated the possible causes using transcranial magnetic stimulation. The patient was able to walk and climb stairs spontaneously without any assistance at 3 weeks after onset. However, she was unable to intentionally move her right lower limb although she understood what she supposed to do. The motor evoked potential evoked by transcranial magnetic stimulation from the right lower limb was within the normal range, indicating that the corticospinal tract innervating the right lower limb was uninjured. Thus, we thought that her motor dysfunction was not induced by motor weakness, and confirmed her symptoms as aprax- ia. In addition, these results also suggest that transcranial magnetic stimulation is helpful for diagnosing apraxia.

Changes in sensorimotor regions of the cerebral cortex in congenital amusia:a case-control study

Perceiving pitch is a central function of the human auditory system;congenital amusia is a disorder of pitch perception.The underlying neural mechanisms of congenital amusia have been actively discussed.However,little attention has been paid to the changes in the motor rain within congenital amusia.In this case-control study,17 participants with congenital amusia and 14 healthy controls underwent functional magnetic resonance imaging while resting with their eyes closed.A voxel-based degree centrality method was used to identify abnormal functional network centrality by comparing degree centrality values between the congenital amusia group and the healthy control group.We found decreased degree centrality values in the right primary sensorimotor areas in participants with congenital amusia relative to controls,indicating potentially decreased centrality of the corresponding brain regions in the auditory-sensory motor feedback network.We found a significant positive correlation between the degree centrality values and the Montreal Battery of Evaluation of Amusia scores.In conclusion,our study identified novel,hitherto undiscussed candidate brain regions that may partly contribute to or be modulated by congenital amusia.Our evidence supports the view that sensorimotor coupling plays an important role in memory and musical discrimination.The study was approved by the Ethics Committee of the Second Xiangya Hospital,Central South University,China(No.WDX20180101GZ01)on February 9,2019.

Nischarin-siRNA delivered by polyethyleniminealginate nanoparticles accelerates motor function recovery after spinal cord injury

A previous study by our group found that inhibition of nischarin promotes neurite outgrowth and neuronal regeneration in Neuro-2 a cells and primary cortical neurons.In recent years,more and more studies have shown that nanomaterials have good prospects in treatment of spinal cord injury.We proposed that small interfering RNA targeting nischarin（Nis-si RNA） delivered by polyethyleneimine-alginate（PEIALG） nanoparticles promoted motor function recovery in rats with spinal cord injury.Direct microinjection of 5 μL PEI-ALG/Nis-si RNA into the spinal cord lesion area of spinal cord injury rats was performed.From day 7 after surgery,Basso,Beattie and Bresnahan score was significantly higher in rats from the PEI-ALG/Nis-si RNA group compared with the spinal cord injury group and PEI-ALG/Control-si RNA group.On day 21 after injection,hematoxylin-eosin staining showed that the necrotic area was reduced in the PEI-ALG/Nis-si RNA group.Immunohistochemistry and western blot assay results confirmed successful inhibition of nischarin expression and increased protein expression of growth-associated protein-43 in the PEI-ALG/Nis-si RNA group.These findings suggest that a complex of PEI-ALG nanoparticles and Nis-si RNA effectively suppresses nischarin expression,induces expression of growth-associated protein-43,and accelerates motor function recovery after spinal cord injury.

Is effect of transcranial direct current stimulation on visuomotor coordination dependent on task difficulty?

Transcranial direct current stimulation （tDCS）, an emerging technique for non-invasive brain stimulation, is increasingly used to induce changes in cortical excitability and modulate motor behavior, especially for upper limbs. The purpose of this study was to investigate the effects of tDCS of the primary motor cortex on visuomotor coordination based on three levels of task difficulty in healthy subjects. Thirty-eight healthy participants underwent real tDCS or sham tDCS. Using a single-blind, sham-controlled crossover design, tDCS was applied to the primary motor cortex. For real tDCS conditions, tDCS intensity was 1 mA while stimulation was applied for 15 minutes. For the sham tDCS, electrodes were placed in the same position, but the stimu- lator was turned off after 5 seconds. Visuomotor tracking task, consisting of three levels （levels 1, 2, 3） of difficulty with higher level indicating greater difficulty, was performed before and after tDCS application. At level 2, real tDCS of the primary motor cortex improved the accurate index compared to the sham tDCS. However, at levels 1 and 3, the accurate index was not significantly increased after real tDCS compared to the sham tDCS. These findings suggest that tasks of mod- erate difficulty may improve visuomotor coordination in healthy subjects when tDCS is applied compared with easier or more difficult tasks.

Identification of the primary motor area by three-dimensional reconstruction of the corticospinal tract using diffusion tensor imaging

Functional MRI （fMRI） is widely used as a non-invasive method for the evaluation of pre-operation motor function.However,patients with cortical function impairment,such as those with hemiparesis,can rarely achieve hand clenching,a typical fMRI task for central sulcus identification,and the method is also of limited use in uncooperative children.Thus,it is important to develop a new method for identifying primary motor areas （PMA） in such individuals.This study used corticospinal tractography to identify the PMA in 20 patients with deep-seated brain tumor.Two regions of interest were set within the brainstem for corticospinal tract （CST） fiber tracking：one at the level of the pons and the other at the level of the cerebral peduncle.The CST fiber tracking results and fMRI activation signals were merged with three-dimensional anatomic MRI findings.The consistency of identifying the PMA by CST and fMRI was analyzed.fMRI activation signals were distributed mainly in the contralateral central sulcus around the omega-shaped hand knob.The CST consistently propagated from the pons and cerebral peduncle to the suspected PMA location.There was a good correlation between CST fiber tracking results and fMRI activation signals in terms of their abilities to identify the PMA.The differences between fMRI and CST fiber tracking findings may result from our functional task,which consisted only of hand movements.Our results indicate that diffusion tensor imaging is a useful brain mapping technique for identifying the PMA in paralyzed patients and uncooperative children.

Supplementary motor area deactivation impacts the recovery of hand function from severe peripheral nerve injury

Although some patients have successful peripheral nerve regeneration,a poor recovery of hand function often occurs after peripheral nerve injury.It is believed that the capability of brain plasticity is crucial for the recovery of hand function.The supplementary motor area may play a key role in brain remodeling after peripheral nerve injury.In this study,we explored the activation mode of the supplementary motor area during a motor imagery task.We investigated the plasticity of the central nervous system after brachial plexus injury,using the motor imagery task.Results from functional magnetic resonance imaging showed that after brachial plexus injury,the motor imagery task for the affected limbs of the patients triggered no obvious activation of bilateral supplementary motor areas.This result indicates that it is difficult to excite the supplementary motor areas of brachial plexus injury patients during a motor imagery task,thereby impacting brain remodeling.Deactivation of the supplementary motor area is likely to be a serious problem for brachial plexus injury patients in terms of preparing,initiating and executing certain movements,which may be partly responsible for the unsatisfactory clinical recovery of hand function.

Effect of Lumbar Spinal Point Injection on Sitting Function in Children with Cerebral Palsy

Objective: To observe the effect of lumbar spinal point injection on sitting function in children with cerebral palsy. Method: Sixty-two children with post-confirmed cerebral palsy were randomly divided into control group and treatment group, 31 each. The control group was given conventional rehabilitation treatment, and the treatment group was given lumbar chiropspinal acupoint injection on the basis of the treatment method of the control group. After 3 consecutive courses of treatment, the sitting score of the two groups before and after treatment (GMFM88) was used to evaluate the sitting score before and after treatment. Outcome: Before treatment, the two groups were evaluated and the differences were not statistically significant (p > 0.05), which was comparable. The two groups (GMFM88) after treatment had significantly increased the differential values, and the difference was statistically significant compared with the same group before treatment (p Conclusion: Conventional rehabilitation combined with lumbar spinal point injection can effectively improve the sitting motor function of children with cerebral palsy.

Changes in brain functional network connectivity after stroke

Studies have shown that functional network connection models can be used to study brain net- work changes in patients with schizophrenia. In this study, we inferred that these models could also be used to explore functional network connectivity changes in stroke patients. We used independent component analysis to find the motor areas of stroke patients, which is a novel way to determine these areas. In this study, we collected functional magnetic resonance imaging datasets from healthy controls and right-handed stroke patients following their first ever stroke. Using independent component analysis, six spatially independent components highly correlat- ed to the experimental paradigm were extracted. Then, the functional network connectivity of both patients and controls was established to observe the differences between them. The results showed that there were 11 connections in the model in the stroke patients, while there were only four connections in the healthy controls. Further analysis found that some damaged connections may be compensated for by new indirect connections or circuits produced after stroke. These connections may have a direct correlation with the degree of stroke rehabilitation. Our findings suggest that functional network connectivity in stroke patients is more complex than that in hea- lthy controls, and that there is a compensation loop in the functional network following stroke. This implies that functional network reorganization plays a very important role in the process of rehabilitation after stroke.

Magnetic resonance diffusion tensor imaging with fluorescein sodium dyeing for surgery of gliomas in brain motor functional areas

Background Tumor surgery in brain motor functional areas remains challenging. Novel techniques are being developed to gain maximal and safe resection for brain tumor surgery. Herein, we assessed the magnetic resonance diffusion tensor imaging （MR-DTI） and fluorescein sodium dyeing （FLS） guiding technique for surgery of glioma located in brain motor functional areas. Methods Totally 83 patients were enrolled according to our inclusion and exclusion criteria （56 patients in experimental group, 27 patients in control group）. In the experimental group, the surgical approach was designed by DTI imaging, which showed the relationship between the tumor and motor tract. The range of resection in the operation was determined using the FLS-stained area, which recognized the tumor and its infiltrated tissue. The traditional routine method was used in the control group. Postoperatively, all patients underwent enhanced brain MRI within 72 hours to ascertain the extent of resection. Patients were followed in our outpatient clinic over 6-24 months. Neurological deficits and Karnofsky scoring （KPS） were evaluated. Results There were no significant differences in balance test indexes of preoperative data （sex, age, lesion location and volume, and neurological deficits before operation） and diagnosis of histopathology between the two groups. There was a trend in the experimental group for greater rates of gross total resection （80.4% vs. 40.7%）, and the paralysis rate caused by surgery was lower in experimental （25.0%） vs. control （66.7%） groups （P 〈0.05）. The 6-month KPS in the low-grade and high-grade gliomas was 91＋11 and 73＋26, respectively, in the experimental group vs. 82＋9 and 43＋27, respectively, in the control group （P 〈0.05 for both）. Conclusions MR-DTI and FLS dye guiding for surgery of glioma located in brain motor functional areas can increase the gross total resection rate, decrease the paralysis rate caused by surgery, and improve patient quality of life compared with traditional glioma surgery.

General Neural Process in Cycling Exercise

Performance in cycling is frequently related to metabolic or biomechanical factors.Overall,the contribution of the neu-rophysiological system during cycling is often poorly considered in performance optimization.Yet,cycling is a complex whole-body physical exercise that necessitates specific coordination and fine control of motor output to manage the dif-ferent intensities.The ability to produce different levels of intensity of exercise would require optimizing many functions of the central nervous system from the brain’s treatment of sensory signals to complex motor command execution via the corticospinal pathway.This review proposes an integrative approach to the factors that could influence cycling performance,based on neurophysiological and cognitive markers.First,we report data relying on brain activity signals,to account for the different brain areas and cognitive functions involved.Then,because the motor command is highly dependent upon its regulation along the corticospinal pathway,we expose the modulation of corticospinal and spinal excitabilities during cycling.We present these later by reviewing the literature of studies using transcranial magnetic or percutaneous nerve stimulations.Finally,we describe a model of neural and cognitive adjustments that occur with acute and chronic cycling practices,with several areas of improvement focusing on these factors,including mental and cognitive training.

Dopaminergic Dysfunction and Glucose Metabolism Characteristics in Parkin-Induced Early-Onset Parkinson’s Disease Compared to Genetically Undetermined Early-Onset Parkinson’s Disease

While early-onset Parkinson’s disease(EOPD)caused by mutations in the parkin gene(PRKN)tends to have a relatively benign course compared to genetically undetermined(GU)-EOPD,the exact underlying mechanisms remain elusive.We aimed to search for the differences between PRKN-EOPD and GU-EOPD by dopamine transporter(DAT)and glucose metabolism positron-emission-tomography(PET)imaging.Twelve patients with PRKN-EOPD and 16 with GU-EOPD who accepted both ^(11)C-2b-carbomethoxy-3b-(4-trimethylstannylphenyl)tropane(^(11)C-CFT)and ^(18)F-fluorodeoxyglucose PET were enrolled.The ^(11)C-CFT uptake was analyzed on both regional and voxel levels,whereas glucose metabolism was assessed in a voxel-wise fashion.Correlations between DAT and glucose metabolism imaging,DAT imaging and clinical severity,as well as glucose metabolism imaging and clinical severity were explored.Both clinical symptoms and DAT-binding pat-terns in the posterior putamen were highly symmetrical in patients with PRKN-EOPD,and dopaminergic dysfunction in the ipsilateral putamen was severer in patients with PRKN-EOPD than GU-EOPD.Meanwhile,the DAT binding was associ-ated with the severity of motor dysfunction in patients with GU-EOPD only.Patients with PRKN-EOPD showed increased glucose metabolism in the contralateral medial frontal gyrus(supplementary motor area(SMA)),contralateral substantia nigra,contralateral thalamus,and contralateral cerebellum.Notably,glucose metabolic activity in the contralateral medial frontal gyrus was inversely associated with regional DAT binding in the bilateral putamen.Patients with PRKN-EOPD showed enhanced metabolic connectivity within the bilateral putamen,ipsilateral paracentral and precentral lobules,and the ipsilateral SMA.Collectively,compared to GU-EOPD,PRKN-EOPD is characterized by symmetrical,more severe dopaminergic dysfunction and relative increased glucose metabolism.Meanwhile,SMA with elevated glucose metabolism and enhanced connectivity may act as compensatory mechanisms in PRKN-EOPD.

合谷穴与面口部特异性联系的脑网络功能研究

Objective:This study was designed to observe the effect of electroacupuncture at Hégǔ(合谷L14),or Hòuxī(后溪SI3) or Wàiguān(外关TE5) acupoints on the function of the brain regions of a healthy human,and to explore the neural information mechanism of a specific connection between LI4 and the facialoral area from the point of view of the brain function connection network.A further objective was to enrich knowledge of the specific connection between the body surface and the meridian route,and the specificity of acupoint effects.Methods:A total of 30 healthy volunteers were randomly assigned to LI4,SI3,and TE5 groups.The members of each group were stimulated with electroacupuncture,and their heads were scanned using fMRI.DPARSFA 2.4 and REST 1.8 software were used for data preprocessing and statistical analysis.The paired t-test was used within group and the double sample t-test was used for two-group comparisons.Results:In healthy people,left LI4 with electroacupuncture mainly caused a decrease of the functional connection of the right orofacial motor area of the brain,which remained decreased after removing the needle.When LI4 was compared with SI3 and TE5,LI4 caused a more significant decline in the functional connection of the right side of the brain during acupuncture.Conclusions:Acupuncture at LI4 has a significant effect on the function of the face-and mouth-related areas in the brain,and there is a continuous effect.It is suggested that LI4 and the face and mouth have a specific relationship in the brain,which is most obvious during acupuncture.