Transcranial electrical stimulation over visual cortex evokes 2 phosphenes with a retinal origin 3
نویسنده
چکیده
36 37 Transcranial electrical stimulation (tES) is a promising therapeutic tool for a range of 38 neurological diseases. Understanding how the small currents used in tES spread across the scalp 39 and penetrate the brain will be important for the rational design of tES therapies. 40 41 Alternating currents applied transcranially above visual cortex induce the perception of flashes 42 of light (phosphenes). This makes the visual system a useful model to study tES. One hypothesis 43 is that tES generates phosphenes by direct stimulation of the cortex underneath the 44 transcranial electrode. Here, we provide evidence for the alternative hypothesis that 45 phosphenes are generated in the retina by current spread from the occipital electrode. 46 47 Building upon the existing literature, we first confirm that phosphenes are induced at lower 48 currents when electrodes are placed farther away from visual cortex and closer to the eye. 49 Second we explain the temporal frequency tuning of phosphenes based on the well-known 50 response properties of primate retinal ganglion cells. Third, we show that there is no difference 51 in the time it takes to evoke phosphenes in the retina, or by stimulation above visual cortex. 52 53 Together, these findings suggest that phosphenes induced by tES over visual cortex originate in 54 the retina. From this we infer that tES currents spread well beyond the area of stimulation, and 55 are unlikely to lead to focal neural activation. Novel stimulation protocols that optimize current 56 distributions are needed to overcome these limitations of tES. 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
منابع مشابه
Bart Krekelberg evokes phosphenes with a retinal origin Transcranial electrical stimulation over visual cortex
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Transcranial electrical stimulation over visual cortex evokes phosphenes with a retinal origin.
Transcranial electrical stimulation (tES) is a promising therapeutic tool for a range of neurological diseases. Understanding how the small currents used in tES spread across the scalp and penetrate the brain will be important for the rational design of tES therapies. Alternating currents applied transcranially above visual cortex induce the perception of flashes of light (phosphenes). This mak...
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Number: 949 Submitted By: Kohitij Kar Last Modified: December 1 2010 Retinal And Cortical Effects Of Transcranial Electric Stimulation Kohitij Kar, Bart Krekelberg Center for Molecular and Behavioral Neuroscience, Rutgers University Transcranial electric current stimulation (tES) of the human brain is assumed to affect cortical excitability by invoking subthreshold modulation of neuronal activi...
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