Intraoperative monitoring study of ipsilateral motor evoked potentials in scoliosis surgery

Ipsilateral motor evoked potentials (MEPs) in spinal cord surgery intraoperative monitoring is not well studied. We show that ipsilateral MEPs have significantly larger amplitudes and were elicited with lower stimulation intensities than contralateral MEPs. The possible underlying mechanisms are discussed based on current knowledge of corticospinal pathways. Ipsilateral MEPs may provide additional information on the integrity of descending motor tracts during spinal surgery monitoring

Mutant TDP-43 and FUS Cause Age-Dependent Paralysis and Neurodegeneration in C. elegans

Mutations in the DNA/RNA binding proteins TDP-43 and FUS are associated with Amyotrophic Lateral Sclerosis and Frontotemporal Lobar Degeneration. Intracellular accumulations of wild type TDP-43 and FUS are observed in a growing number of late-onset diseases suggesting that TDP-43 and FUS proteinopathies may contribute to multiple neurodegenerative diseases. To better understand the mechanisms of TDP-43 and FUS toxicity we have created transgenic Caenorhabditis elegans strains that express full-length, untagged human TDP-43 and FUS in the worm's GABAergic motor neurons. Transgenic worms expressing mutant TDP-43 and FUS display adult-onset, age-dependent loss of motility, progressive paralysis and neuronal degeneration that is distinct from wild type alleles. Additionally, mutant TDP-43 and FUS proteins are highly insoluble while wild type proteins remain soluble suggesting that protein misfolding may contribute to toxicity. Populations of mutant TDP-43 and FUS transgenics grown on solid media become paralyzed over 7 to 12 days. We have developed a liquid culture assay where the paralysis phenotype evolves over several hours. We introduce C. elegans transgenics for mutant TDP-43 and FUS motor neuron toxicity that may be used for rapid genetic and pharmacological suppressor screening

H-magnetic resonance spectroscopy: diagnostic tool in recurrent headache in systemic lupus erythematosus. A case report

We describe serial MR-spectroscopy studies in a patient with systemic lupus erythematosus and headache. We used MR-spectroscopy to monitor disease activity during periods with and without headache.MR-spectroscopy investigates metabolic alterations and was used to explore the pathophysiological mechanism involved in the complications of systemic lupus erythematosus.Our patient underwent serial conventional MRI and MR-spectroscopy at times of controlled and uncontrolled headache, with or without visual aura.MR-spectroscopy showed an increase in the choline/creatine ratio in thalamus and posterior white matter only during periods of uncontrolled headache with visual aura. Conventional MRI scans were normal at all times.MR-spectroscopy should be used in the diagnosis and follow-up of headache in patients with systemic lupus erythematosus. Keywords: Systemic lupus erythematosus, Headache, H-MRS, Metabolic alteration

Motor cortex excitability in chronic fatigue syndrome.

OBJECTIVE:To use transcranial magnetic stimulation (TMS) to define motor cortical excitability in chronic fatigue syndrome (CFS) subjects during a repetitive, bilateral finger movement task. METHODS:A total of 14 CFS patients were tested and compared with 14 age-matched healthy control subjects. TMS of the motor cortex (5% above threshold) was used to elicit motor evoked potentials (MEPs). Subjects performed regular (3-4/s) repetitive bilateral opening-closing movements of the index finger onto the thumb. MEPs of the first dorsal interosseus (FDI) were measured before, immediately following exercise periods of 30, 60 and 90 s, and after 15 min of rest. RESULTS:Performance, defined by rate of movement, was significantly slower in CFS subjects (3.5/s) than in controls (4. 0/s) independent of the hand measured. The rate, however, was not significantly affected by the exercise duration for either group. The threshold of TMS to evoke MEPs from the FDI muscle was significantly higher in CFS than in control subjects, independent of the hemisphere tested. A transient post-exercise facilitation of MEP amplitudes immediately after the exercise periods was present in controls independent of the hemisphere tested, but was absent in CFS subjects. A delayed facilitation of MEPs after 15-30 min of rest was restricted to the non-dominant hemisphere in controls; delayed facilitation was absent in CFS subjects. CONCLUSIONS:Individuals with CFS do not show the normal fluctuations of motor cortical excitability that accompany and follow non-fatiguing repetitive bimanual finger movements

Neurophysiological and functional MRI evidence of reorganization of cortical motor areas in cerebral arteriovenous malformation

Functional magnetic resonance imaging (fMRI) research has shown that brain arteriovenous malformations (AVMs) lead to reorganization of cortical motor areas. Since it is known that blood oxygenation level-dependent signal in fMRI may be influenced by the hemodynamic perturbation associated with the presence of the AVM, in the present study, a combined exploration with fMRI and transcranial magnetic stimulation was performed in a patient with a right rolandic AVM in order to explore the relationship between neuronal and hemodynamic activity. The combined protocol of investigation adopted in this study was able to provide significant information regarding neuronal activity of the different cortical areas that partake to post-lesional reorganization

Delayed facilitation of motor cortical excitability following repetitive finger movements.

ObjectivesTo define motor cortical excitability changes occurring at various times after non-fatiguing bimanual exercise of the index fingers.MethodsTwenty healthy right-handed subjects were studied with transcranial magnetic stimulation (TMS) of the right non-dominant hemisphere. They performed regular (3-4/s) repetitive opening-closing bilateral movements of the index finger onto the thumb. Motor evoked potentials (MEPs) of the left first dorsal interosseus (FDI) and rate of the repetitive finger movements were determined (1) before exercise, (2) immediately following 3 exercise periods of 30, 60 and 90 s, and (3) over a subsequent 30 min rest period.ResultsRate of movement did not show significant change during any of the exercise periods but did increase significantly when tested after 15 min of rest. MEPs immediately after 30 and 60 s of exercise were facilitated whereas MEPs after 90 s of exercise did not differ from baseline measures. MEP amplitudes were significantly increased after rest of approximately 15 min compared to the baseline MEPs. In contrast, motor potentials evoked by peripheral nerve stimulation were unchanged throughout the experimental test periods.ConclusionsMotor cortical excitability relating to an intrinsic finger muscle (FDI) was facilitated beginning 15 min after a brief period of non-forceful, repetitive activity of that muscle. This delayed facilitation of motor cortex after exercise may represent a form of short-term potentiation of motor cortical excitability