Brain Stimul
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Clinical Trial
Intraoperative microelectrode recording for the delineation of subthalamic nucleus topography in Parkinson's disease.
The subthalamic nucleus (STN) as an effective target for deep brain stimulation (DBS) in advanced Parkinson's disease is functionally divided into the dorsolateral sensorimotor and the ventromedial limbic and associative parts. To implant electrodes for DBS close to the sensorimotor region is considered crucial for optimal motor benefit and for avoidance of potential cognitive and behavioral side effects. ⋯ Among all parameters analyzed in the study, spike pattern is the only convenient electrophysiologic parameter for the differentiation of STN subregions in patients with Parkinson's disease. The autocorrelogram-based analysis of spike activity seems to be of certain value for the delineation of the dorsolateral STN and might therefore facilitate the precise electrode implantation for DBS.
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Transcranial direct current stimulation (tDCS) is a noninvasive technique that has been investigated as a therapeutic tool for different neurologic disorders. Neuronal excitability can be modified by application of DC in a polarity-specific manner: anodal tDCS increases excitability, while cathodal tDCS decreases excitability. Previous research has shown that simultaneous bilateral tDCS of the human motor cortex facilitates motor performance in the anodal stimulated hemisphere much more than when the same hemisphere is stimulated using unilateral anodal motor cortex tDCS. ⋯ This is the first study in which cortical excitability before and after bilateral motor cortex tDCS was extensively evaluated, and the effects of bilateral tDCS were compared with unilateral motor cortex tDCS. Simultaneous bilateral tDCS seems to be a useful tool to obtain increases in cortical excitability of one hemisphere whereas causing decreases of cortical excitability in the contralateral hemisphere (e.g.,to treat stroke).
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Empathic responses to facial cues are a main social competency. Both appraisal processes (facial emotion detection) and self-perceived empathy (empathic responsiveness) in response to emotional faces are thought to be related to empathic behavior, although no systematic analysis has been performed to assess their relationship. ⋯ The ability to monitor emotional cues and the behavioral empathic responsiveness to emotional situations was shown to be partially compromised in the case of frontal activity disruption, highlighting the main role of the sensorimotor system for empathic social skills.
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Neuromodulatory techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have been increasingly studied as possible treatments for many neurological and psychiatric disorders. tDCS is capable of inducing changes in regional cerebral blood flow in both cortical and subcortical structures, as shown by positron emission tomography studies, and might conceivably affect hypothalamic and autonomic nervous system functions. However, it remains unknown whether acute changes in autonomic or hypothalamic functions may be triggered by conventional tDCS protocols. ⋯ The changes in hand temperature and cortisol levels, having occurred in both the sham and experimental groups, probably reflect a non-specific stress response to a new procedure. There were no significant changes in autonomic functions, ventilation rate or core body temperature that can be attributed to conventional tDCS applied to healthy volunteers.