To assess the relationship between Bayesian MUNE and histological motor neuron counts in wild-type mice and in an animal model of ALS.
Methods
We performed Bayesian MUNE paired with histological counts of motor neurons in the lumbar spinal cord of wild-type mice and transgenic SOD1G93A mice that show progressive weakness over time. We evaluated the number of acetylcholine endplates that were innervated by a presynaptic nerve.
Results
In wild-type mice, the motor unit number in the gastrocnemius muscle estimated by Bayesian MUNE was approximately half the number of motor neurons in the region of the spinal cord that contains the cell bodies of the motor neurons supplying the hindlimb crural flexor muscles. In SOD1G93A mice, motor neuron numbers declined over time. This was associated with motor endplate denervation at the end-stage of disease.
Conclusion
The number of motor neurons in the spinal cord of wild-type mice is proportional to the number of motor units estimated by Bayesian MUNE. In SOD1G93A mice, there is a lower number of estimated motor units compared to the number of spinal cord motor neurons at the end-stage of disease, and this is associated with disruption of the neuromuscular junction.
Significance
Our finding that the Bayesian MUNE method gives estimates of motor unit numbers that are proportional to the numbers of motor neurons in the spinal cord supports the clinical use of Bayesian MUNE in monitoring motor unit loss in ALS patients. 相似文献
The origin of the startle reflex lies in the caudal brainstem; it can be elicited by an unexpected stimulus resulting in a bilateral activation of many muscles. Two subsequent responses can be measured during EMG recordings; after the initial motor reflex, lasting until about 150 ms, a second response can occur. The second response contains more emotional and voluntary behavioral responses. Clinically, syndromes with hyperstartling as common feature can be divided into three groups: hyperekplexia, stimulus-induced disorders, and neuropsychiatric disorders. Classification of startle syndromes within these three groups remains challenging. Generalized stiffness at birth, excessive startling and temporary generalized stiffness after being startled point towards hyperekplexia. Stimulus-induced disorders are distinguished by careful clinical and neurophysiological evaluation, including video recordings. Neuropsychiatric disorders usually have additional behavioural and psychiatric symptoms. Polymyographic EMG startle recordings exhibit an exaggeration of the initial motor startle reflex in hyperekplexia, while neuropsychiatric startle syndromes demonstrate a variable response pattern and abnormal behavioural features. Neurophysiological investigation of the startle reflex can help to further delineate between the startle syndromes and unravel the aetiology of neuropsychiatric startle disorders. 相似文献
Context: Acquired copper deficiency represents a rare cause of progressive myelopathy presenting with sensory ataxia and spastic gait. The time interval from neurological symptoms onset to diagnosis of myelopathy ranges from 2 months to several years in almost all cases, mimicking the clinical course of subacute combined degeneration due to vitamin B12 deficiency.
Findings: A 60-year-old man, without any gastrointestinal symptoms, developed over the course of one week rapidly progressive gait imbalance, tingling and numbness in his feet and ascending lower limb weakness. Spine magnetic resonance imaging revealed hyperintensity involving cervical and dorsal posterior columns of spinal cord. Blood analysis revealed undetectable serum copper levels, low serum ceruloplasmin and positive serum Immunoglobulin A anti-tissue transglutaminase. Upper gastrointestinal endoscopy was performed revealing duodenal villous atrophy consistent with a malabsorption pattern. A gluten-free diet in association with intravenous then oral copper supplementation prompted sustained normalization of serum copper levels and progressive clinical improvement.
Conclusion/Clinical Relevance: We report a rare case of myelopathy induced by copper deficiency secondary to undiagnosed celiac disease, peculiarly presenting with a subacute onset. This case expands the neurological presentation and clinical course of myelopathy due to acquired copper deficiency. We suggest investigation of copper deficiency in patients presenting with subacute or even acute sensory ataxia and spastic gait. Detection of hypocupremia in patients without a previous history of gastric surgery should lead to diagnostic testing for celiac disease even in the absence of any obvious gastrointestinal symptoms. 相似文献
According to Bleuler (1911), language impairments were indicative of thought disorders, a fundamental feature of schizophrenia. The objectives of the present review are twofold: (1) to present the clinical interest of the use of the tests of proverbs and metaphors comprehension for the evaluation of the characteristics of thought disorders in schizophrenia, and to highlight the heterogeneity of the forms of their interpretations; (2) to present the results from neuroimaging and neurophysiological studies of metaphor comprehension in order to identify the neurocognitive mechanisms underlying metaphorical language comprehension of patients with schizophrenic disorders. Results from the reviewed clinical applications of proverbs tests showed that thought disorders in individuals with schizophrenia are illustrated by different forms of proverb interpretations: literal, concrete, idiosyncratic, over-inclusiveness and unconventional. Results from the reviewed brain imaging and neurophysiological studies showed that these different forms of figurative misinterpretations may be related to different neurocognitive mechanisms: concreteness appears to be related to the dysfunction of the left inferior frontal gyrus and inverted brain lateralization during metaphor processing in individuals with schizophrenia compared to healthy individuals. During novel metaphor comprehension, which is highly effortful, individuals with schizophrenia, relative to controls, demonstrate increased activation of the right precuneus, a region that mediates complex and highly integrated functions including retrieval of episodic memory and mental imagery. These results may suggest that individuals with schizophrenia use mental imagery to support comprehension of both literal and metaphoric language. Furthermore, it was demonstrated that over-inclusive thinking, which is exhibited by individuals with schizophrenia during figurative language comprehension, could be related to very early right hemispheric hyper-activation (when a left early activation is expected) and to reduced bilateral brain activity during semantic processing. Such as reversed brain activation may explain why the individuals with schizophrenia are relatively over reliant on early-stage coarse or large semantic processing and may be prone to form meanings that are idiosyncratic and highly unconventional. 相似文献
Unverricht–Lundborg disease (ULD) is the most common form of progressive myoclonus epilepsy. Cerebellar dysfunction may appear over time, contributing along with myoclonus to motor disability. The purpose of the present work was to clarify the motor and neurophysiological characteristics of ULD patients.
Methods
Nine patients with genetically proven ULD were evaluated clinically (medical history collected from patient charts, the Scale for the Assessment and Rating of Ataxia and Unified Myoclonus Rating Scale). Neurophysiological investigations included EEG, surface polymyography, long-loop C-reflexes, somatosensory evoked potentials, EEG jerk-locked back-averaging (JLBA) and oculomotor recordings. All patients underwent brain MRI. Non-parametric Mann-Whitney tests were used to compare ULD patients’ oculomotor parameters with those of a matched group of healthy volunteers (HV).
Results
Myoclonus was activated by action but was virtually absent at rest and poorly induced by stimuli. Positive myoclonus was multifocal, often rhythmic and of brief duration, with top-down pyramidal temporospatial propagation. Cortical neurophysiology revealed a transient wave preceding myoclonus on EEG JLBA (n = 8), enlarged somatosensory evoked potentials (n = 7) and positive long-loop C-reflexes at rest (n = 5). Compared with HV, ULD patients demonstrated decreased saccadic gain, increased gain dispersion and a higher frequency of hypermetric saccades associated with decreased peak velocity.
Conclusion
A homogeneous motor pattern was delineated that may represent a ULD clinical and neurophysiological signature. Clinical and neurophysiological findings confirmed the pure cortical origin of the permanent myoclonus. Also, oculomotor findings shed new light on ULD pathophysiology by evidencing combined midbrain and cerebellar dysfunction. 相似文献
IntroductionMotor evoked potentials (MEP) in response to anteroposterior transcranial (AP) magnetic stimulation (TMS) are sensitive to the TMS pulse shape. We are now able to isolate distinct pulse properties, such as pulse width and directionality and evaluate them individually. Different pulse shapes induce different effects, likely by stimulating different populations of neurons. This implies that not all neurons respond in the same manner to stimulation, possibly, because individual segments of neurons differ in their membrane properties.ObjectivesTo investigate the effect of different pulse widths and directionalities of TMS on MEP latencies, motor thresholds and plastic aftereffects of rTMS.MethodsUsing a controllable pulse stimulator TMS (cTMS), we stimulated fifteen subjects with quasi-unidirectional TMS pulses of different pulse durations (40 μs, 80 μs and 120 μs) and determined thresholds and MEP AP latencies. We then compared the effects of 80 μs quasi-unidirectional pulses to those of 80 μs pulses with different pulse directionality characteristics (0.6 and 1.0 M ratios). We applied 900 pulses of the selected pulse shapes at 1 Hz.ResultsThe aftereffects of 1 Hz rTMS depended on pulse shape and duration. 40 and 80 μs wide unidirectional pulses induced inhibition, 120 μs wide pulses caused excitation. Bidirectional pulses induced inhibition during the stimulation but had facilitatory aftereffects. Narrower pulse shapes caused longer latencies and higher resting motor thresholds (RMT) as compared to wider pulse shapes.ConclusionsWe can tune the aftereffects of rTMS by manipulating pulse width and directionality; this may be due to the different membrane properties of the various neuronal segments such as dendrites.SignificanceTo date, rTMS frequency has been the main determinant of the plastic aftereffects. However, we showed that pulse width also plays a major role, probably by recruiting novel neuronal targets. 相似文献
To assess whether ICU caregivers can correctly read and interpret continuous EEG (cEEG) data displayed with the computer algorithm NeuroTrend (NT) with the main attention on seizure detection and determination of sedation depth.
Methods
120 screenshots of NT (480 h of cEEG) were rated by 18 briefly trained nurses and biomedical analysts. Multirater agreements (MRA) as well as interrater agreements (IRA) compared to an expert opinion (EXO) were calculated for items such as pattern type, pattern location, interruption of recording, seizure suspicion, consistency of frequency, seizure tendency and level of sedation.
Results
MRA as well as IRA were almost perfect (80–100%) for interruption of recording, spike-and-waves, rhythmic delta activity and burst suppression. A substantial agreement (60–80%) was found for electrographic seizure patterns, periodic discharges and seizure suspicion. Except for pattern localization (70.83–92.26%), items requiring a precondition and especially those who needed interpretation like consistency of frequency (47.47–79.15%) or level of sedation (41.10%) showed lower agreements.
Conclusions
The present study demonstrates that NT might be a useful bedside monitor in cases of subclinical seizures. Determination of correct sedation depth by ICU caregivers requires a more detailed training.
Significance
Computer algorithms may reduce the workload of cEEG analysis in ICU patients. 相似文献
An improved chromatographic method was developed to isolate and purify polypeptides and proteins from the crude venom of the Taiwan cobra Naja naja atra. The procedure devised is simple, easy to reproduce, and enables large scale isolation of almost all polypeptides and proteins in this cobra venom. Six pure polypeptide fractions of the venom were isolated and characterized using gel filtration on Sephadex G50 (medium), ion exchange chromatography on SP-Sephadex C25, desalting on Sephadex G25 (fine) and preparative HPLC on a RPC 18 column. The neuromuscular activity of these fractions was tested on the chick biventer cervicis nerve-muscle preparation and their toxicity (LD50) was determined after i.v. administration in mice. Their antinociceptive activity was tested in the mouse abdominal test by i.v. application. Two of these polypeptide samples had major physiological effects: one acted as a cardiotoxin causing reversible myocardial contractures with no effect on muscle twitches elicited by nerve stimulation (NS); another was a neurotoxin that blocked muscle contractions in response to NS and exogenously added acetylcholine. The cardiotoxic fraction was identified as CTX I, a well-known cardiotoxin present in this venom, and the neurotoxin was identified as neurotoxin-α with an LD50 in mice of 0.075 mg/kg. 相似文献