Effects of Transcranial Direct Current Stimulation Associated With Physical Exercise: a Metaplasticity Study

Before the two phases of the study, the subjects will be evaluate in the following aspects: anxiety by the beck anxiety inventory; depression by the beck depression inventory; level of physical exercise by the international physical activity questionnaire; stress by the stress perceived scale 10.

In the first phase, the subjects will be undergo to 4 conditions: (i) 15 minutes of physical exercise with moderate intensity; (ii) 10 minutes of physical exercise with high intensity; (iii) 30 minutes of physical exercise with mild intensity; (iv) 15 or 30 minutes of rest. Before each condition, cortical excitability will be measure through the Transcranial magnetic stimulation by motor evoked potential (MEP); the blood glucose level will be evaluate by glucometer. The MEP also will be done immediately after the physical exercise and in every 5 min for 30 after the end of exercise/rest. The blood glucose level will be done immediately after the exercise..

In the second phase, the subjects will be undergo to 6 conditions: (i) anodal tDCS + physical exercise 1; (ii) anodal tDCS + physical exercise 2; (iii) cathodal tDCS + physical exercise 1; (iv) cathodal tDCS + physical exercise 2; (v) sham tDCS + physical exercise 1; (vi) sham tDCS + physical exercise 2. The intensity and time of physical exercise depends of the results of the previous phase and will be determine after the end of phase 1. In this phase, the blood glucose level will be evaluate before and immediately the physical exercise. The cortical excitability will be evaluate through the Transcranial magnetic stimulation by the following measures: motor evoked potential - before the tDCS,after tDCS, immediately , 10, 20, 30, 60, 90 minutes after the exercise; resting motor threshold - before tdcs, immediately and 90 minutes after the exercise; recruitment curve - before tdcs, immediately and 90 minutes after the exercise.

tDCS condition During tDCS application, patients will be seated in a comfortable chair with head and arms rests. Current will be applied by a DC stimulator (NeuroConn, Germany) using a pair of saline-soaked sponge electrodes (surface 35 and 36cm²).

tDCS will be applied to Cz and Oz according to International 10-20 EEG system. In the anodal tDCS, the anode will be placed in Cz and cathode in Oz. In the cathodal tDCS the inverse position will be done. Parameters of current intensity and duration (dose) used were previously established in poststroke patients: 2 mA stimulation intensity for 20 minutes with current ramping up and down of 10 seconds each.