Poststimulation time interval-dependent effects of motor cortex anodal tDCS on reaction-time task performance

Abstract

Anodal transcranial direct current stimulation (tDCS) induces long-term potentiation-like plasticity, which is associated with long-lasting effects on different cognitive, emotional, and motor performances. Specifically, tDCS applied over the motor cortex is considered to improve reaction time in simple and complex tasks. The timing of tDCS relative to task performance could determine the efficacy of tDCS to modulate performance. The aim of this study was to compare the effects of a single session of anodal tDCS (1.5 mA, for 15 min) applied over the left primary motor cortex (M1) versus sham stimulation on performance of a go/no-go simple reaction-time task carried out at three different time points after tDCS-namely, 0, 30, or 60 min after stimulation. Performance zero min after anodal tDCS was improved during the whole course of the task. Performance 30 min after anodal tDCS was improved only in the last block of the reaction-time task. Performance 60 min after anodal tDCS was not significantly different throughout the entire task. These findings suggest that the motor cortex excitability changes induced by tDCS can improve motor responses, and these effects critically depend on the time interval between stimulation and task performance.

Anodal Occipital Transcranial Direct Current Stimulation Enhances Perceived Visual Size Illusions

“…Moreover, this enhancement was transient, lasting no more than 15 min, consistent with previous findings (Molero-Chamizo et al, 2018;Kuo et al, 2013;Merzagora et al, 2010;Lang, Nitsche, Paulus, Rothwell, & Lemon, 2004). The functional effects of tDCS on cognitive tasks weaken with time, which agrees with the fact that the enhancement of cortical excitability is max immediately after anodal stimulation and then declines gradually (Muthalib, Besson, Dutta, Hayashibe, & Perrey, 2019;Molero-Chamizo et al, 2018;Zheng, Alsop, & Schlaug, 2011). The absence of a cathodal effect on context sensitivity in the current study may be attributed to a putative ceiling effect; that is, the surrounding context has been optimally suppressed by the visual system, and cathodal stimulation cannot strengthen the suppression further.…”

“…Therefore, in the current study, the enhancement of context sensitivity induced by anodal stimulation was likely caused by the reduction of GABA concentration in early visual cortex, which weakened the suppression of the surrounding inducers and resulted in the enhancement of context sensitivity. Moreover, this enhancement was transient, lasting no more than 15 min, consistent with previous findings (Molero-Chamizo et al, 2018;Kuo et al, 2013;Merzagora et al, 2010;Lang, Nitsche, Paulus, Rothwell, & Lemon, 2004). The functional effects of tDCS on cognitive tasks weaken with time, which agrees with the fact that the enhancement of cortical excitability is max immediately after anodal stimulation and then declines gradually (Muthalib, Besson, Dutta, Hayashibe, & Perrey, 2019;Molero-Chamizo et al, 2018;Zheng, Alsop, & Schlaug, 2011).…”

TDCS effects on pointing task learning in young and old adults

“…This finding is consistent with Shmuelof et al, showing M1-activation from the beginning of APT learning 67 and highlights the important role of M1 in initial skill acquisition in YA 7,91 . Brain activity prior to learning is undoubtedly an important predictor of subsequent motor performance 92 and previous studies also found tDCS applied before learning facilitated subsequent skill acquisition rates [93][94][95] . By contrast, no tDCS-induced effect was found on spatial variability in either group.…”

Feasibility and effectiveness of remotely supervised tDCS combined with computerized cognitive training for patients with stroke: A randomized sham-controlled study

“…Although previous o ine application of tDCS for more than 30 minutes did not have a signi cant effect [35], by the long-term potentiation mechanism, generalization of the tDCS effect is induced and, even if tDCS is applied o ine, it would be able to show the effect [34]. More research is needed regarding the timing of tDCS application to CT.…”