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Brain-machine interfaces (BMIs) use signals recorded directly from the brain to control an external device, such as a computer cursor or a prosthetic limb. These control signals have been recorded from different levels of the brain, from field potentials at the scalp or cortical surface to single neuron action potentials. At present, the more invasive(More)
Recent reports have suggested that chaos control techniques may be useful for electrically manipulating epileptiform bursting behavior in neuronal ensembles. Because the dynamics of spontaneous in vitro bursting had not been well determined previously, analysis of this behavior in the rat hippocampus was performed. Epileptiform bursting was induced in(More)
The development of an epileptic "mirror" focus in an area of the brain contralateral to the primary epileptic focus typically evolves over days in the experimental setting after status epilepticus or electrical kindling of the primary focal region. In contrast, we observed the rapid development of an apparent mirror focus in the contralateral hippocampus(More)
Epilepsy is a relatively common disease, afflicting 1%-2% of the population, yet many epileptic patients are not sufficiently helped by current pharmacological therapies. Recent reports have suggested that chaos control techniques may be useful for electrically manipulating epileptiform bursting behavior in vitro and could possibly lead to an alternative(More)
Computational studies of the head utilizing finite element models (FEMs) have been used to investigate a wide variety of brain-electromagnetic (EM) field interaction phenomena including magnetic stimulation of the head using transcranial magnetic stimulation (TMS), direct electric stimulation of the brain for electroconvulsive therapy, and(More)
Most neuronal ensembles are nonlinear excitable systems. Thus it is becoming common to apply principles derived from nonlinear dynamics to characterize neuronal systems. One important characterization is whether such systems contain deterministic behavior or are purely stochastic. Unfortunately, many methods used to make this distinction do not perform well(More)
Neuronal populations throughout the brain achieve levels of synchronous electrophysiological activity as a consequence of both normal brain function as well as during pathological states such as in epileptic seizures. Understanding this synchrony and being able to quantitatively assess the dynamics with which neuronal oscillators across the brain couple(More)
Transcranial magnetic stimulation (TMS) is a noninvasive technique that can alter brain activation by inducing electrical current in neurons using dynamic magnetic fields. Because of its painless nature, clinical usage has expanded to diagnostic purposes and therapeutic treatments. However, several issues and challenges still exist for TMS. A very limited(More)
Neuronal populations in the brain achieve levels of synchronous electrophysiological activity during both normal brain function and pathological states such as epileptic seizures. Understanding how the dynamics of neuronal oscillators in the brain evolve from normal to diseased states is a critical component toward decoding such complex behaviors. In this(More)
OBJECTIVE Better visualization of the intracranial aneurysm may improve surgical outcomes. To this aim, we evaluated the effectiveness of using virtual endoscopy (VE) during intracranial aneurysm surgery. METHODS Fifty-eight patients with 63 intracranial aneurysms were enrolled in this study. Every patient was examined by digital subtraction angiography(More)