Progress in brain research
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Spinal cord injury (SCI) is a serious clinical problem for which no suitable therapeutic strategies have been worked out so far. Recent studies suggest that the SCI and its pathophysiological responses could be altered by systemic exposure to nanoparticles. Thus, SCI when made in animals intoxicated with engineered nanoparticles from metals or silica dust worsened the outcome. ⋯ This indicates that nanoparticles depending on the exposure and its usage could induce both neurotoxicity and neuroprotection. This review discusses the potential adverse or therapeutic utilities of nanoparticles in SCI largely based on our own investigations. In addition, possible mechanisms of nanoparticle-induced exacerbation of cord pathology or enhanced neuroprotection following nanodrug delivery is described in light of recently available data in this rapidly emerging field of nanoneurosciences.
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Review Historical Article
Functional neurosurgery for movement disorders: a historical perspective.
Since the 1960s, deep brain stimulation and spinal cord stimulation at low frequency (30 Hz) have been used to treat intractable pain of various origins. For this purpose, specific hardware have been designed, including deep brain electrodes, extensions, and implantable programmable generators (IPGs). In the meantime, movement disorders, and particularly parkinsonian and essential tremors, were treated by electrolytic or mechanic lesions in various targets of the basal ganglia, particularly in the thalamus and in the internal pallidum. ⋯ The recent development of nanotechnologies allows the design of totally new systems expanding the field of deep brain stimulation. These new techniques will make it possible to not only inhibit or excite deep brain structures to alleviate abnormal symptoms but also open the field for the use of recording cortical activities to drive neuroprostheses through brain-computer interfaces. The new field of compensation of deficits will then become part of the field of functional neurosurgery.
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Alzheimer's disease (AD) is the most prevalent form of neurodegeneration; however, therapies to prevent or treat AD are inadequate. Amyloid-beta (Abeta) protein accrues in cortical senile plaques, one of the key neuropathological hallmarks of AD, and is elevated in brains of early onset AD patients in a small number of families that bear certain genetic mutations, further implicating its role in this devastating neurological disease. In addition, soluble Abeta oligomers have been shown to be detrimental to neuronal function. ⋯ Preclinical trials in nonhuman primates, and human clinical trials using similar Abeta immunogens, are now underway. Abeta immunotherapy looks promising but must be made safer and more effective at generating antibody titers in the elderly. It is hoped that these novel immunogens will enhance Abeta antibody generation across a broad population and avoid the adverse events seen in the earlier clinical trial.
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Review
The use of repetitive transcranial magnetic stimulation (rTMS) for the treatment of spasticity.
Spasticity is a common disorder in patients with injury of the brain and spinal cord, especially in patients affected by multiple sclerosis (MS). In MS, spasticity is a major cause of long-term disability, it significantly impacts daily activities and quality of life and is only partially influenced by traditional spasmolytic drugs. ⋯ The H reflex is a reliable electrophysiologic measure of the stretch reflex, and has been used in previous studies to test the effects of rTMS of the motor cortex on spinal circuitry. Based on these premises, originating from physiological studies in normal subjects, some studies have demonstrated that rTMS of the leg motor cortex can be beneficial in the management of spasticity by enhancing corticospinal tract excitability and reducing H reflex amplitude.
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The recent upsurge in placebo research has demonstrated the sound neurobiological substrate of a phenomenon once believed to be only patient mystification, or at best a variable to control in clinical trials, bringing about a new awareness of its potential exploitation to the patient's benefit and framing it as a positive context effect, with the power to influence the therapy outcome. Placebo effects have been described both in the experimental setting and in different clinical conditions, many of which are of neurological interest. ⋯ A body of evidence from neurochemical, pharmacological, and neuroimaging studies points to the involvement of neural pathways specific to single conditions, such as the activation of the endogenous antinociceptive system during placebo analgesia or the release of dopamine in the striatum of parkinsonian patients experiencing placebo reduction of motor impairment. The possible clinical applications of placebo studies range from the design of clinical trials incorporating specific recommendations and minimizing the use of placebo arms to the optimization of the context surrounding the patient, in order to maximize the placebo component present in any treatment.