Stimulus Stimulus will be combination of quasi-trapezoidal cathodic and rectangular anodic current pulses. Precisely, the resulting current, biphasic and charge balanced combination will be composed of a quasi-trapezoidal cathodic phase with a square leading edge with different intensity ic , a plateau tc of 300 μs, and exponentially decaying phase texp of 500 μs, followed by a wide rectangular anodic phase ta of alow current magnitude ia. Anodic phase ia will be one-tenth of the magnitude in the cathodic phase. However, the width of the anodic phase ta will be dependent upon the charge injected in the cathodic phase: the greater the charge, the wider the anodic phase.