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The mechanism of essential tremor (ET) is unclear. Animal models of tremor and functional imaging studies in ET predict that the cerebellum and a cerebellar recipient thalamic nucleus (ventral intermediate, Vim) should exhibit oscillatory activity during rest and during tremor due to abnormal olivo-cerebellar activity. Physiologic responses of 152 single(More)
Over the past year, a number of conceptual and mathematical models of the basal ganglia and their interactions with other areas of the brain have appeared in the literature. Even though the models each differ in significant ways, several computational principles, such as convergence, recurrence and competition, appear to have emerged as common themes of(More)
Single unit and imaging studies have shown that the cerebellum is especially active during the acquisition phase of certain motor and cognitive tasks. These data are consistent with the hypothesis that particular sensorimotor procedures are acquired and stored in the cerebellar cortex and that this knowledge can then be exported to the cerebral cortex and(More)
Strokes and other forms of injury to the central nervous system cause changes in function because of the injuries themselves and indirectly because injuries cause expression of neural plasticity. Studies in humans undergoing neurosurgical procedures for implantation of electrodes for deep brain stimulation and for making lesions in the brain have(More)
Lesion or degeneration of the cerebellum can profoundly impair adaptive control of reaching in humans. Computational models have proposed that internal models that help control movements form in the cerebellum and influence planned motor output through the cerebello-thalamo-cortical pathway. However, lesion studies of the cerebellar thalamus have not(More)
Animal studies suggest that an olivocerebello-bulbospinal pathway mediates harmaline induced tremor, which resembles essential tremor in humans. However, recent evidence suggests that thalamocortical pathways participate in essential tremor. Thalamic single neuron activity has been analysed during thalamotomy for essential tremor. It has been shown by(More)
We review the techniques of physiological localization of the site for ventralis intermedius (Vim) thalamotomy or implantation of Vim-deep brain stimulation (DBS) for treatment of parkinsonian, essential, and intention tremor. Both microelectrode and semi-microelectrode techniques are reviewed. We believe the use of microelectrode and semi-microelectrode(More)
The projection from the retina develops into a precise map of the visual world on the surface of the tectum. The search for molecular position cues that mediate map formation has recently yielded a tectal molecule that exerts a repulsion to fibers from the entire temporal half retina. This molecule appears not to function in the generally accepted gradient(More)
The mechanism of parkinsonian tremor may involve a central oscillator, peripheral feedback to the central nervous system (CNS), or both. The thalamus or the globus pallidus is the most likely site for a central oscillator and would be predicted to generate thalamic tremor-related activity characterized, respectively, by calcium spike-associated bursts and(More)
Microelectrode studies of single units in the human thalamus during stereotactic surgery offer a unique opportunity to study the organization and plasticity of the sensory thalamus. In this review the authors present results using single-unit microelectrode recording in the mapping of human sensory thalamus in a variety of patients. First they outline the(More)