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Cathodal HD-tDCS on the right V5 improves motion perception in humans.

Zito GA, Senti T, Cazzoli D, Müri RM, Mosimann UP, Nyffeler T, Nef T - Front Behav Neurosci (2015)

Bottom Line: The results showed significant improvement in motion perception in the left hemifield after cathodal HD-tDCS, but not in shape perception.Sham and anodal HD-tDCS did not affect performance.The specific effect of influencing performance of visual tasks by modulating the excitability of the neurons in the visual cortex might be explained by the complexity of perceptual information needed for the tasks.

View Article: PubMed Central - PubMed

Affiliation: Gerontechnology and Rehabilitation Group, University of Bern Bern, Switzerland.

ABSTRACT
Brain lesions in the visual associative cortex are known to impair visual perception, i.e., the capacity to correctly perceive different aspects of the visual world, such as motion, color, or shapes. Visual perception can be influenced by non-invasive brain stimulation such as transcranial direct current stimulation (tDCS). In a recently developed technique called high definition (HD) tDCS, small HD-electrodes are used instead of the sponge electrodes in the conventional approach. This is believed to achieve high focality and precision over the target area. In this paper we tested the effects of cathodal and anodal HD-tDCS over the right V5 on motion and shape perception in a single blind, within-subject, sham controlled, cross-over trial. The purpose of the study was to prove the high focality of the stimulation only over the target area. Twenty one healthy volunteers received 20 min of 2 mA cathodal, anodal and sham stimulation over the right V5 and their performance on a visual test was recorded. The results showed significant improvement in motion perception in the left hemifield after cathodal HD-tDCS, but not in shape perception. Sham and anodal HD-tDCS did not affect performance. The specific effect of influencing performance of visual tasks by modulating the excitability of the neurons in the visual cortex might be explained by the complexity of perceptual information needed for the tasks. This provokes a "noisy" activation state of the encoding neuronal patterns. We speculate that in this case cathodal HD-tDCS may focus the correct perception by decreasing global excitation and thus diminishing the "noise" below threshold.

No MeSH data available.


Related in: MedlinePlus

Line charts of the results of the Speed Task, the Shape Task, and the Alertness Task. In the graphs, the performance represents the ratio between the two compared images. Values close to 1 depict high performance. Error bars represent the standard error of the mean. (A) results of the Speed Task, the asterisks depicts a significant difference at p < 0.05 as assessed by Tukey’s HSD post hoc tests. (B) results of the Shape Task. (C) results of the Alertness Task.
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Figure 5: Line charts of the results of the Speed Task, the Shape Task, and the Alertness Task. In the graphs, the performance represents the ratio between the two compared images. Values close to 1 depict high performance. Error bars represent the standard error of the mean. (A) results of the Speed Task, the asterisks depicts a significant difference at p < 0.05 as assessed by Tukey’s HSD post hoc tests. (B) results of the Shape Task. (C) results of the Alertness Task.

Mentions: The results of the visual tests and the alertness test are shown in Figure 5.


Cathodal HD-tDCS on the right V5 improves motion perception in humans.

Zito GA, Senti T, Cazzoli D, Müri RM, Mosimann UP, Nyffeler T, Nef T - Front Behav Neurosci (2015)

Line charts of the results of the Speed Task, the Shape Task, and the Alertness Task. In the graphs, the performance represents the ratio between the two compared images. Values close to 1 depict high performance. Error bars represent the standard error of the mean. (A) results of the Speed Task, the asterisks depicts a significant difference at p < 0.05 as assessed by Tukey’s HSD post hoc tests. (B) results of the Shape Task. (C) results of the Alertness Task.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585077&req=5

Figure 5: Line charts of the results of the Speed Task, the Shape Task, and the Alertness Task. In the graphs, the performance represents the ratio between the two compared images. Values close to 1 depict high performance. Error bars represent the standard error of the mean. (A) results of the Speed Task, the asterisks depicts a significant difference at p < 0.05 as assessed by Tukey’s HSD post hoc tests. (B) results of the Shape Task. (C) results of the Alertness Task.
Mentions: The results of the visual tests and the alertness test are shown in Figure 5.

Bottom Line: The results showed significant improvement in motion perception in the left hemifield after cathodal HD-tDCS, but not in shape perception.Sham and anodal HD-tDCS did not affect performance.The specific effect of influencing performance of visual tasks by modulating the excitability of the neurons in the visual cortex might be explained by the complexity of perceptual information needed for the tasks.

View Article: PubMed Central - PubMed

Affiliation: Gerontechnology and Rehabilitation Group, University of Bern Bern, Switzerland.

ABSTRACT
Brain lesions in the visual associative cortex are known to impair visual perception, i.e., the capacity to correctly perceive different aspects of the visual world, such as motion, color, or shapes. Visual perception can be influenced by non-invasive brain stimulation such as transcranial direct current stimulation (tDCS). In a recently developed technique called high definition (HD) tDCS, small HD-electrodes are used instead of the sponge electrodes in the conventional approach. This is believed to achieve high focality and precision over the target area. In this paper we tested the effects of cathodal and anodal HD-tDCS over the right V5 on motion and shape perception in a single blind, within-subject, sham controlled, cross-over trial. The purpose of the study was to prove the high focality of the stimulation only over the target area. Twenty one healthy volunteers received 20 min of 2 mA cathodal, anodal and sham stimulation over the right V5 and their performance on a visual test was recorded. The results showed significant improvement in motion perception in the left hemifield after cathodal HD-tDCS, but not in shape perception. Sham and anodal HD-tDCS did not affect performance. The specific effect of influencing performance of visual tasks by modulating the excitability of the neurons in the visual cortex might be explained by the complexity of perceptual information needed for the tasks. This provokes a "noisy" activation state of the encoding neuronal patterns. We speculate that in this case cathodal HD-tDCS may focus the correct perception by decreasing global excitation and thus diminishing the "noise" below threshold.

No MeSH data available.


Related in: MedlinePlus