Journal of neuroscience methods
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J. Neurosci. Methods · Jan 2010
A novel method for modeling facial allodynia associated with migraine in awake and freely moving rats.
Migraine is a neurovascular disorder that induces debilitating headaches associated with multiple symptoms including facial allodynia, characterized by heightened responsivity to normally innocuous mechanical stimuli. It is now well accepted that immune activation and immune-derived inflammatory mediators enhance pain responsivity, including the trigeminal system. Nociceptive ("pain" responsive) trigeminal nerves densely innervate the cranial meninges. ⋯ While surgery alone does not alter immune activation markers, TNF or IL6 mRNA and/or protein, it does decrease gene expression and increase protein expression of IL-1 at 4 days after surgery. Using this model we show the induction of facial allodynia in response to supradural administration of either the HIV glycoprotein gp120 or inflammatory soup (bradykinin, histamine, serotonin, and prostaglandin E2), and the induction of hindpaw allodynia in our model after inflammatory soup. This model allows time- and dose-dependent assessment of the relationship between changes in meningeal inflammation and corresponding exaggerated pain behaviors.
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J. Neurosci. Methods · Nov 2009
A method for rapid derivation and propagation of neural progenitors from human embryonic stem cells.
Neuronal loss is a common feature of many neurological disorders, including stroke, Parkinson's disease, Alzheimer's disease and traumatic brain injury. Human embryonic stem cell (hESC)-derived neural progenitors (NPs) may provide new ways of treatment for several diseases and injuries in the brain, as well as enhance our understanding of early human development. Here we report a method for rapid generation of proliferating NPs from feeder free cultures of undifferentiated hESCs. ⋯ After the first passage, adherent monolayer progenitors are derived that express early neuroectodermal and progenitor markers, such as Nestin, Sox1, Sox2, Sox3, Internexin, Musashi-1, NCAM, and Pax6. This novel protocol renders hESCs suitable for large scale progenitor production and long-term propagation, and the progenitors have the capacity to differentiate in vitro into all three neural lineages (neurons, astrocytes and oligodendrocytes). This method allows rapid, cost-efficient production of expandable progenitors that may be a source of cells for the restoration of cellular and functional loss after neurodegeneration and/or provide a useful source of progenitor cells for studying early brain development.
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Continuous recording of Visual Evoked Potentials (VEPs) and functional Magnetic Resonance Imaging (fMRI) exploits the VEPs high temporal resolution and the fMRI high spatial resolution. In this work, we present a new method of continuous VEPs/fMRI recording to study visual function in seven normal subjects. Our real-time artifact filtering is characterized by a procedure based on an analytical study of echo-planar imaging (EPI) sequence parameters related electro-encephalogram (EEG)-artifact shapes. ⋯ No significant decrease in signal-to-noise ratio was observed in case of EEG recording simultaneously with MR acquisition; similarly, transient and steady-state VEPs parameters were comparable during fMRI acquisition and in the off-phase of fMRI recording. We also applied this method to one patient with optic neuritis, and, compared with controls, found different results. We suggest that our technique can be reliably used to investigate the function of human visual cortex and properly correlate the electrophysiological and functional neuroimaging related changes.
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J. Neurosci. Methods · Nov 2009
Measuring and tracking eye movements of a behaving archer fish by real-time stereo vision.
The archer fish (Toxotes chatareus) exhibits unique visual behavior in that it is able to aim at and shoot down with a squirt of water insects resting on the foliage above water level and then feed on them. This extreme behavior requires excellent visual acuity, learning, and tight synchronization between the visual system and body motion. This behavior also raises many important questions, such as the fish's ability to compensate for air-water refraction and the neural mechanisms underlying target acquisition. ⋯ Based on a stereo vision system and a unique triangulation method that corrects for air-glass-water refraction, we are able to measure a full three-dimensional pose of the fish eye and body with high temporal and spatial resolution. Our method, being generic, can be applied to studying the behavior of marine animals in general. We demonstrate how data collected by our method may be used to show that the hunting behavior of the archer fish is composed of surfacing concomitant with rotating the body around the direction of the fish's fixed gaze towards the target, until the snout reaches in the correct shooting position at water level.
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J. Neurosci. Methods · Oct 2009
Investigating the depth electrode-brain interface in deep brain stimulation using finite element models with graded complexity in structure and solution.
Deep brain stimulation (DBS) is an increasingly used surgical therapy for a range of neurological disorders involving the long-term electrical stimulation of various regions of the human brain in a disorder specific manner. Despite being used for the last 20 years, the underlying mechanisms are still not known, and disputed. In particular, when the electrodes are implanted into the human brain, an interface is created with changing biophysical properties which may impact on stimulation. ⋯ However, the frequency-dependent models are necessary as the waveform shaping has a major influence on the activation of neuronal fibres. We also investigate anatomical effects on the electric field, by taking specific account of the ventricular system in the human brain. Taken together, these models allow us to visualise the static, dynamic and target specific properties of the DBS-induced field in the surrounding brain regions.