Authors: L Schweid R J Rushmore A ValeroCabré
Publish Date: 2008/01/15
Volume: 186, Issue: 3, Pages: 409-417
Abstract
Transcranial direct current stimulation tDCS has recently undergone a resurgence in popularity as a powerful tool to noninvasively manipulate brain activity While tDCS has been used to alter functions tied to primary motor and visual cortices its impact on extrastriate visual areas involved in visuospatial processing has not yet been examined In the current study we applied tDCS to the cat visuoparietal VP cortex and assayed performance in a paradigm designed to assess the capacity to detect localize and orient to static targets appearing at different spatial eccentricities within the visual field Real or sham cathodal tDCS was unilaterally applied to the VP cortex and orienting performance was assessed during online immediately after offline Experiments 1 and 2 and 1 or 24 h after the end of the tDCS stimulation Experiment 2 Performance was compared to baseline data collected immediately prior to stimulation Real but not sham tDCS induced significant decreases in performance for static visual targets presented in the contrastimulated visual hemifield The behavioral impact of tDCS was most apparent during the online and immediate offline periods The tDCS effect decayed progressively over time and performance returned to baseline levels ∼60 min after stimulation These results are consistent with the effects of both invasive and noninvasive deactivation methods applied to the same brain region and indicate that tDCS has the potential to modify neuronal activity in extrastriate visual regions and to sculpt brain activity and behavior in normal and neurologically impaired subjectsWe are grateful to Felipe Fregni and Tim Wagner for their insightful comments during the preparation of this project and to Brian Jaap Ben Wolfe Laura Rigolo and Linda Afifi for their assistance in training Finally we thank Laura Rigolo for providing the excellent illustration in Fig 2 The current work was supported in part by the National Institutes of Health NS32137 and NS33975 to BP/MMAVC
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