Publications by authors named "Cheolki Im"

Objectives: Transcranial direct current stimulation (tDCS) is an emerging neuromodulation technique. The effect of tDCS can vary significantly depending on electrode position and current intensity, making it crucial to find an optimized tDCS montage. However, because of the high computational load, most tDCS optimization approaches have been performed with a limited number of candidates for electrode positions, such as 10-10 or 10-20 international channel configurations.

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Article Synopsis
  • Transcranial direct current stimulation (tDCS) is a non-invasive technique that uses weak electrical currents to adjust brain activity, but its effectiveness can vary widely among individuals due to factors like brain atrophy.
  • A study involving 180 MRI scans categorized participants by Alzheimer's disease and sex to analyze how brain atrophy impacts the electric fields generated by tDCS across different brain regions.
  • Results showed significant variations in cerebrospinal fluid (CSF) volume and electric field patterns, indicating that factors like brain atrophy influence tDCS outcomes, highlighting the need for further research to refine its therapeutic applications.
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Electrical brain stimulation is a treatment method for brain disorder patients. The majority of patients with a severe brain disorder have brain atrophy. However, it is not clearly understood if electrical brain stimulation is effective even to brain atrophy.

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Transcranial electrode stimulation (tES), one of the techniques used to apply non-invasive brain stimulation (NIBS), modulates cortical activities by delivering weak electric currents through scalp-attached electrodes. This emerging technique has gained increasing attention recently; however, the results of tES vary greatly depending upon subjects and the stimulation paradigm, and its cellular mechanism remains unclear. In particular, there is a controversy over the factors that determine the cortical response to tES.

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Transcranial electrical stimulation (tES), which modulates cortical excitability via electric currents, has attracted increasing attention because of its application in treating neurologic and psychiatric disorders. To obtain a better understanding of the brain areas affected and stimulation's cellular effects, a multi-scale model was proposed that combines multi-compartmental neuronal models and a head model. While one multi-scale model of tES that used straight axons reported that the direction of electric field (EF) is a determining factor in a neuronal response, another model of transcranial magnetic stimulation (TMS) that used arborized axons reported that EF magnitude is more crucial than EF direction because of arborized axons' reduced sensitivity to the latter.

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Electrical brain stimulation (EBS) has been actively researched because of its clinical application and usefulness in brain research. However, its effect on individual neurons remains uncertain, as each neuron's response to EBS is highly variable and dependent on its morphology and the axis in which a neuron lies. Hence, our goal was to investigate the way that neuronal morphology affects the cellular response to extracellular stimulation from multiple directions.

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Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation method that is convenient and popular in clinical use. However, there is a practical issue in applying tDCS; it is difficult to optimize the montage for each individual because of inherent inter-subject variability. Thus, the stimulation effect of such individual anatomical head variation has been investigated using anatomically realistic models.

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