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Grid Electrodes (grid + electrode)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Manipulation of microparticles for construction of array patterns by negative dielectrophoresis using multilayered array and grid electrodes

BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2009
Kosuke Ino
Abstract In this study, a useful method was developed to fabricate array patterns of microparticles not on electrode surfaces, but on arbitrary surfaces, using negative-dielectrophoresis (n-DEP). First, electrodes were designed and electric field simulations were performed to manipulate microparticles toward target areas. Based on the simulation results, multilayered array and grid (MLAG) electrodes, consisting of array electrodes surrounded by insulated regions and a grid electrode, were fabricated for the formation of localized, non-uniform electric fields. The MLAG electrode was mounted to a target substrate in a face-to-face configuration with a spacer. When an AC voltage (4.60,Vrms and 1,MHz) was applied to the MLAG electrode, array patterns of 6 and 20,µm diameter microparticles were rapidly fabricated on the target substrate with ease. The results suggest that MLAG electrodes can be widely applied for the fabrication of biochips including cell arrays. Biotechnol. Bioeng. 2009; 104: 709,718 © 2009 Wiley Periodicals, Inc. [source]

Seizures Lead to Elevation of Intracranial Pressure in Children Undergoing Invasive EEG Monitoring

EPILEPSIA, Issue 6 2007
Aash K Shah
Summary:,Purpose: To study the effects of intracranial subdural grid electrode placement and seizures on intracranial pressure (ICP) in children undergoing invasive EEG monitoring. Methods: Sixteen children with pharmacoresistant epilepsy who underwent two-stage epilepsy surgery with subdural grid placement were included in the study. The ICP was recorded at baseline and with each seizure prospectively. A variety of seizure parameters including type of seizure, length of seizure, extent of seizure spread, and number of subdural grid electrodes inserted were analyzed retrospectively and correlated with the change in ICP. Results: A total of 48 seizures in 16 children were studied. The mean baseline ICP correlated positively with age of the child. Generalized tonic,clonic seizures were associated with the highest rise in ICP. Similarly, ICP rise was associated with seizures involving more electrodes indicating a larger area of brain participating in the seizure. Conclusion: Seizures in general and generalized tonic,clonic seizures, in particular, increase ICP temporarily in patients who are undergoing invasive EEG monitoring with subdural grids. [source]

Brain,computer interfacing based on cognitive control

ANNALS OF NEUROLOGY, Issue 6 2010
Mariska J. Vansteensel PhD
Objective Brain,computer interfaces (BCIs) translate deliberate intentions and associated changes in brain activity into action, thereby offering patients with severe paralysis an alternative means of communication with and control over their environment. Such systems are not available yet, partly due to the high performance standard that is required. A major challenge in the development of implantable BCIs is to identify cortical regions and related functions that an individual can reliably and consciously manipulate. Research predominantly focuses on the sensorimotor cortex, which can be activated by imagining motor actions. However, because this region may not provide an optimal solution to all patients, other neuronal networks need to be examined. Therefore, we investigated whether the cognitive control network can be used for BCI purposes. We also determined the feasibility of using functional magnetic resonance imaging (fMRI) for noninvasive localization of the cognitive control network. Methods Three patients with intractable epilepsy, who were temporarily implanted with subdural grid electrodes for diagnostic purposes, attempted to gain BCI control using the electrocorticographic (ECoG) signal of the left dorsolateral prefrontal cortex (DLPFC). Results All subjects quickly gained accurate BCI control by modulation of gamma-power of the left DLPFC. Prelocalization of the relevant region was performed with fMRI and was confirmed using the ECoG signals obtained during mental calculation localizer tasks. Interpretation The results indicate that the cognitive control network is a suitable source of signals for BCI applications. They also demonstrate the feasibility of translating understanding about cognitive networks derived from functional neuroimaging into clinical applications. ANN NEUROL 2010 [source]