Progress in brain research
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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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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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Perceptual decision making is the process by which information gathered from sensory systems is combined and used to influence our behavior. Importantly, however, the route from perception to action is not a one-way street, rather, perception and action interact continuously. ⋯ We conclude that there is evidence for the liaison of action and perception in simple decision-making tasks. This framework may also be extended to reward-based decision making in humans.
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This chapter describes current findings from the research into postoperative cognitive dysfunction (POCD) following cardiac and non-cardiac surgery in older adults. The evidence suggests that a significant proportion of patients show POCD in the early weeks following surgery and anesthesia. Specific domains of cognition are affected, especially memory. ⋯ Increasing age is among the most consistently reported patient-related risk factor. Other factors more directly related to the surgery and anesthesia are likely to contribute to the pathogenesis of POCD, including inflammatory processes triggered by the surgical procedure. Animal studies have provided valuable findings otherwise not possible in human studies; these include a correlation between the inflammatory response in the hippocampus and the development of POCD in rodents.
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Impaired urinary dilution leading to water retention and hyponatremia may occur in patients with cardiac failure, cirrhosis, pregnancy, hypothyroidism, glucocorticoid and mineralocorticoid deficiency. The mechanisms for these defects predominantly involve the non-osmotic stimulation of arginine vasopressin release with upregulation of aquaporin 2 water channel expression and trafficking to the apical membrane of the principal cells of the collecting duct. ⋯ They may involve several factors, such as impaired counter-current concentration secondary to downregulation of Na-K-2Cl co-transporter. Vasopressin-resistant downregulation of aquaporin 2 expression has also been described as a factor in impaired urinary concentration.