Dysfunction of the motor system as a specialty of the regulation part of the motor system. A model

Summary The attempt was made to explain dysfunctions of the motor system – analogical to electronic data processing systems – as a speciality of the regulation part of the motor system. Thereby dysfunctions can be seen as misplaced variables in the regulation software with not defined or unknown values of afferences or combination of afferences. This leads to a failure of the corresponding software modul that results in the loss of function which is regulated through this modul. Especially with changing of afference through manual treatment or through needling, a replacement of the variables can be reached and this leads to normal function. With this hypothesis all phenomens of dysfunctions can be explained.      

Hand movement distribution in the motor cortex: the influence of a concurrent task and motor imagery

The aim of this work was to study the relevance of the primary motor cortex (M1) for motor functions different to the simple execution of motor orders. The M1 activity during the performance with individual fingers of a simple motor task (tonic flexion), a motor task that includes a complex motor computation but not motor execution (motor imagery), and a motor task that involves both the computation and execution of movements (phasic movement) was evaluated by functional magnetic resonance imaging (fMRI). The possible influence of other cortical tasks on the M1 activation induced by finger movements was assessed by evaluating the effect of a distracting concurrent task (numeric calculation). Data show that both the dimension of the area activated and the intensity of response were higher during motor planning than during motor execution. There is a mosaic-like distribution for motor-planning M1 functions, with the movement of individual fingers being controlled from several M1 loci. The concurrent mental-task induces a rapid functional reconfiguration of M1, adding M1 subsets to motor programming but excluding others. Present data support the involvement of the M1 in more than just simple motor execution, showing broader and more intense modifications during motor tasks not accompanied by movements (motor imagery) than during the execution of simple motor acts (tonic flexion).     

The motor development of the human being

Spontaneous motor activity and postural reflex reactivity should be distinguished in the motor development of a human being. The central nervous system plays the main role in motor development. Motor development in early infancy (up to 6 month of age) is based on postural static primary reflexes, which assure a stable supine position. The next stages in development, during the second half of the infant's first year, involve the appearance of statokinetic extension reflexes, which enable the infant to change position from crawling on four limbs to standing on two. The complex and active balance reflexes that enable further motor development, so that a five-year-old-child is able to perform all the motor activities of an adult, are formed between 18 and 24 months of age. Careful observations of the infant's psycho-motor skills make it possible to detect disturbances early and apply the proper therapy.     

The microcirculation is the motor of sepsis

Regional tissue distress caused by microcirculatory dysfunction and mitochondrial depression underlies the condition in sepsis and shock where, despite correction of systemic oxygen delivery variables, regional hypoxia and oxygen extraction deficit persist. We have termed this condition microcirculatory and mitochondrial distress syndrome (MMDS). Orthogonal polarization spectral imaging allowed the first clinical observation of the microcirculation in human internal organs, and has identified the pivotal role of microcirculatory abnormalities in defining the severity of sepsis, a condition not revealed by systemic hemodynamic or oxygen-derived variables. Recently, sublingual sidestream dark-field (SDF) imaging has been introduced, allowing observation of the microcirculation in even greater detail. Microcirculatory recruitment is needed to ensure adequate microcirculatory perfusion and the oxygenation of tissue cells that follows. In sepsis, where inflammation-induced autoregulatory dysfunction persists and oxygen need is not matched by supply, the microcirculation can be recruited by reducing pathological shunting, promoting microcirculatory perfusion, supporting pump function, and controlling hemorheology and coagulation. Resuscitation following MMDS must include focused recruitment of hypoxic-shunted microcirculatory units and/or resuscitation of the mitochondria. A combination of agents is required for successful rescue of the microcirculation. Single compounds such as activated protein C, which acts on multiple pathways, can be expected to be beneficial in rescuing the microcirculation in sepsis.     

Self-modulation of primary motor cortex activity with motor and motor imagery tasks using real-time fMRI-based neurofeedback

Advances in fMRI data acquisition and processing have made it possible to analyze brain activity as rapidly as the images are acquired allowing this information to be fed back to subjects in the scanner. The ability of subjects to learn to volitionally control localized brain activity within motor cortex using such real-time fMRI-based neurofeedback (NF) is actively being investigated as it may have clinical implications for motor rehabilitation after central nervous system injury and brain-computer interfaces. We investigated the ability of fifteen healthy volunteers to use NF to modulate brain activity within the primary motor cortex (M1) during a finger tapping and tapping imagery task. The M1 hand area ROI (ROI_m) was functionally localized during finger tapping and a visual representation of BOLD signal changes within the ROI_m fed back to the subject in the scanner. Surface EMG was used to assess motor output during tapping and ensure no motor activity was present during motor imagery task. Subjects quickly learned to modulate brain activity within their ROI_m during the finger-tapping task, which could be dissociated from the magnitude of the tapping, but did not show a significant increase within the ROI_m during the hand motor imagery task at the group level despite strongly activating a network consistent with the performance of motor imagery. The inability of subjects to modulate M1 proper with motor imagery may reflect an inherent difficulty in activating synapses in this area, with or without NF, since such activation may lead to M1 neuronal output and obligatory muscle activity. Future real-time fMRI-based NF investigations involving motor cortex may benefit from focusing attention on cortical regions other than M1 for feedback training or alternative feedback strategies such as measures of functional connectivity within the motor system.     

Akathisia: the syndrome of motor restlessness

Akathisia is a common but frequently unrecognized complication of antipsychotic medication. Affected individuals report an inner discomfort which they attempt to relieve by increased motor activity. This disorder often causes dramatic changes in behavior which may be misinterpreted as signs that more, rather than less, medication is required. Diphenhydramine therapy is often effective in new-onset akathisia. Anticholinergic agents may also be of value.     

Evaluation of the effective connectivity of supplementary motor areas during motor imagery using Granger causality mapping

Brain activation during motor imagery has been studied extensively for years, but only a few of these studies focused on investigating the effective connectivity in the brain. The existence of interactions or closed loop circuits between the SMA and other brain regions during motor imagery still remains unclear. In the present study, selecting the SMA as the region of interest, we used the Granger causality mapping (GCM) method to explore the effective connectivity in the brain during motor imagery. Our results demonstrated that more brain regions showed effective connections to the SMA during the right-hand motor imagery than during the left-hand motor imagery, but the strength of the casual influence during the left-hand motor imagery was stronger than that of the right-hand motor imagery. We further found forward and backward effective connectivity between the SMA and three regions, including the bilateral dorsal premotor area (PMd), the contralateral primary and secondary somatosensory cortex (S1), and the primary motor cortex (M1). these results might indicate how the brain regions were inter-activated during motor imagery.     

Prognostic value of motor evoked potentials in stroke motor outcome

Functional study technologies of the central nervous system (CNS) are fast developing, yielding further objective data for evidence based neurological rehabilitation. Transcranial magnetic stimulation is a safe and non invasive technique of functional investigation of several aspects of the CNS. During the past few years many studies have focused on motor evoked potentials (MEPs) in the investigation of central nervous system and particularly of central motor pathways. Among the various issues of rehabilitative concern in this context, the prognostic value of MEPs of motor outcome after stroke is the most interesting one. The aim of this review, conducted on Medline database, is to find out the current agreement in the literature about this topic and to outline clinical criteria of use of the test. Many of the retrieved papers suggest an added value of MEPs on motor prognosis after first ischemic sylvian stroke, highlighting higher specificity in clinical cases with paralysis or severe paresis in the acute stage. A clinical use of MEPs in specific stroke subgroups might help to plan a more individual rehabilitative project through realistic motor recovery goals and selected techniques of treatment; a more reliable motor prognosis may also be useful for rehabilitation effectiveness research and for a more aimed use of resources.     

运动想象疗法对脑卒中偏瘫患者上肢运动功能的影响

目的:探讨运动想象疗法对脑卒中偏瘫患者上肢运动功能和日常生活活动(ADL)能力的影响。方法:采用随机病例对照方法。经运动想象问卷(KVIQ)评定后,入选的39例脑卒中患者随机分为治疗组(n=20)和对照组(n=19),治疗组用运动想象疗法进行干预。入选时和治疗8周后,用Fugl-Meyer运动功能评分法和改良巴氏指数评定患者的上肢运动功能和ADL能力。结果:同组间治疗前后比较,FMA和MBI均有明显改善,差异有显著性意义(P0.01),治疗后治疗组与对照组之间的FMA和MBI值比较差异有显著性意义(P0.01)。结论:运动想象疗法可明显地促进脑卒中偏瘫患者上肢运动功能和ADL能力。     

Altered resting-state effective connectivity of fronto-parietal motor control systems on the primary motor network following stroke

Previous brain imaging work suggests that stroke alters the effective connectivity (the influence neural regions exert upon each other) of motor execution networks. The present study examines the intrinsic effective connectivity of top-down motor control in stroke survivors (n = 13) relative to healthy participants (n = 12). Stroke survivors exhibited significant deficits in motor function, as assessed by the Fugl-Meyer Motor Assessment. We used structural equation modeling (SEM) of resting-state fMRI data to investigate the relationship between motor deficits and the intrinsic effective connectivity between brain regions involved in motor control and motor execution. An exploratory adaptation of SEM determined the optimal model of motor execution effective connectivity in healthy participants, and confirmatory SEM assessed stroke survivors' fit to that model. We observed alterations in spontaneous resting-state effective connectivity from fronto-parietal guidance systems to the motor network in stroke survivors. More specifically, diminished connectivity was found in connections from the superior parietal cortex to primary motor cortex and supplementary motor cortex. Furthermore, the paths demonstrated large individual variance in stroke survivors but less variance in healthy participants. These findings suggest that characterizing the deficits in resting-state connectivity of top-down processes in stroke survivors may help optimize cognitive and physical rehabilitation therapies by individually targeting specific neural pathway.