%draw target stimuli
Screen('FillOval', mainWindow, tarcol, [mX - radius, mY - stimDist - stimSize, mX + radius, mY - stimDist]);
[targetFlipStart, targetStimOnset] = Screen('Flip', mainWindow);
Screen('Flip', mainWindow, targetStimOnset + 10);
[x, y, buttons] = GetMouse;
if x == mX && y == mY -stimDist - stimYpos
RT = Getsecs - targetStimuOnset;
end