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Deep brain stimulation (DBS) of the subthalamic nucleus markedly improves the motor symptoms of Parkinson's disease, but causes cognitive side effects such as impulsivity. We showed that DBS selectively interferes with the normal ability to slow down when faced with decision conflict. While on DBS, patients actually sped up their decisions under(More)
It takes effort and time to tame one's impulses. Although medial prefrontal cortex (mPFC) is broadly implicated in effortful control over behavior, the subthalamic nucleus (STN) is specifically thought to contribute by acting as a brake on cortico-striatal function during decision conflict, buying time until the right decision can be made. Using the drift(More)
Subthalamic nucleus deep brain stimulation improves motor symptoms and quality of life in advanced Parkinson's disease. As after other life-altering surgeries, suicides have been reported following deep brain stimulation for movement disorders. We sought to determine the suicide rate following subthalamic nucleus deep brain stimulation for Parkinson's(More)
Classical conditioning is abnormal in patients with cerebellar degeneration. Pathological studies have recently demonstrated the finding of Purkinje cell loss in a subset of essential tremor (ET). We studied 10 subjects with long duration ET using a blink reflex conditioning paradigm and compared them with nine controls. A 55.6% reduction in motor learning(More)
Dysphagia is very common in patients with Parkinson disease (PD) and often leads to aspiration pneumonia, the most common cause of death in PD. Current therapies are largely ineffective for dysphagia. Because pharyngeal sensation normally triggers the swallowing reflex, we examined pharyngeal sensory nerves in PD patients for Lewy pathology.Sensory nerves(More)
Dysphagia (impaired swallowing) is common in patients with Parkinson disease (PD) and is related to aspiration pneumonia, the primary cause of death in PD. Therapies that ameliorate the limb motor symptoms of PD are ineffective for dysphagia. This suggests that the pathophysiology of PD dysphagia may differ from that affecting limb muscles, but little is(More)
Parkinson disease (PD) is a neurodegenerative disease primarily characterized by cardinal motor manifestations and CNS pathology. Current drug therapies can often stabilize these cardinal motor symptoms, and attention has shifted to the other motor and nonmotor symptoms of PD that are resistant to drug therapy. Dysphagia in PD is perhaps the most important(More)
A new theoretical framework is used to analyze functions and pathophysiological processes of cortico-basal ganglia-thalamocortical loops and to demonstrate the hierarchical relationships between various loops. All hierarchical levels are built according to the same functional principle: Each loop is a neural optimal control system (NOCS) and includes a(More)
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is now widely used to alleviate symptoms of Parkinson’s disease (PD). The specific aim of this study was to identify posture control measures that may be used to improve selection of DBS parameters in the clinic and this was carried out by changing the DBS stimulation amplitude. A dynamic posture(More)