Efeito da estimulação transcraniana por corrente contínua na aprendizagem motora de curto e longo prazo

Abstract

Studies on motor learning have pointed out several factors that favor short- and longterm motor learning. Among these factors we can mention the structuring of the practice, the direction of the focus of attention, the supply of feedback, as well as neuromodulation via biofeedback and non-invasive stimulations such as Transcranial Direct Current Stimulation (tDCS). However, little is known about the lasting effects of tDCS on long-term learning. Thus, the aim of the study was to verify the effects of the tDCS application on short and long-term motor learning when a memory extinction test was inserted between the recall tests. Twenty adult participants were divided into 2 constant practice groups (n=10): tDCS group and placebo group. An electrical stimulation (1mA) was applied on the primary motor cortex in the EG for 20 minutes before the practice. The GP group received only 36 seconds of stimulation. In the acquisition phase, the task consisted of performing a sequence of touches on a numeric keypad in 120 attempts at absolute target times of 700, 900 and 1,100 ms. and in relative times between keys (22.2% from 2 to 8, 44.4% from 8 to 6 and 33.3% from 6 to 4). The recall test 1 and memory extinction were performed 24 hours and the recall test 2 was performed 10 days after the acquisition, consisting of 12 attempts each. The TE was performed with a new absolute time of 1300 ms. The results showed that tDCS favored learning in the short term, but not in the long term. Possibly, the changes promoted by tDCS do not seem to be sustained when a process of memory extinction is inserted.