The effects of 1 or 2 mA M1 a-tDCS compared to sham tDCS on
motor learning
In the present study, we hypothesized that the groups receiving a-tDCS
at intensities of 1 and 2 mA would show significant improvements in
motor learning compared to the group receiving sham tDCS. The results of
our study not only supported this hypothesis, but also revealed
significant effects on both online and offline motor learning when
compared to the sham group. These findings are consistent with previous
studies conducted by Stagg et al. (2009, 2011), which investigated the
efficacy of 1 mA M1 a-tDCS in motor learning and demonstrated a
facilitative impact on online motor learning (Stagg et al. , 2009;
Stagg et al. , 2011). Furthermore, evidence suggests that a-tDCS
can enhance motor learning by facilitating offline consolidation effects
(Reis et al. , 2009). Additionally, Ciechanski et al. (2017) found
that healthy children exhibited increased motor learning and performance
following 1 mA M1 a-tDCS compared to sham tDCS, with lasting effects
observed up to 6 weeks after stimulation (Ciechanski & Kirton, 2017).
Ambrus et al. also found that anodal stimulation increased offline
learning (Ambrus et al. , 2012). According to the study by Greeley
et al. (2020), the application of 2 mA M1 a-tDCS showed a faster
reduction in RT compared to the sham group (Greeley et al. ,
2020). Moreover, these individuals showed faster relearning after one
year (Greeley et al. , 2020). It seems that 2 mA a-tDCS has
broader and longer-lasting effects on corticospinal excitability, making
it a more potent modulator of neuronal activity (Batsikadze et
al. , 2013; Strube et al. , 2016). Overall, these studies
collectively support our findings that a-tDCS at specific intensities
can improve both online and offline motor learning outcomes compared to
sham stimulation.