System for providing an electrical stimulus to surrounding tissue comprising: a probe (PR1; PR2) with multiple electrodes (Ei); a generator for supplying electrical signals (Si) to the electrodes (Ei) to obtain a field distribution (Fi) in the surrounding tissue; a controller being constructed for controlling the generator to provide: in a first state a first distribution of the electrical signals (Si) to the electrodes (Ei) for generating a first field distribution, and in a second state a second distribution of the electrical signals (Si) to the electrodes (Ei) for generating a second field distribution, wherein the first distribution is more symmetrical with respect to the electrodes (Ei) than the second distribution, and the electrical signals (Si) to obtain a sum of electrical stimulation currents (ISi) supplied to the probe (PR1; PR2) being in the second state is lower than in the first state, characterized in that the controller is constructed for adjusting the electrical signals (Si) to the electrodes (Ei) such that the generated field distribution (Fi) gradually changes from the first field distribution in the first state into the second field distribution in the second state or the other way around, wherein the total amount of electrical stimulation currents in the tissue is decreased when the field distribution in the tissue is made less symmetrical. a probe (PR1; PR2) with multiple electrodes (Ei); a generator for supplying electrical signals (Si) to the electrodes (Ei) to obtain a field distribution (Fi) in the surrounding tissue; a controller being constructed for controlling the generator to provide: in a first state a first distribution of the electrical signals (Si) to the electrodes (Ei) for generating a first field distribution, and in a second state a second distribution of the electrical signals (Si) to the electrodes (Ei) for generating a second field distribution, wherein the first distribution is more symmetrical with respect to the electrodes (Ei) than the second distribution, and the electrical signals (Si) to obtain a sum of electrical stimulation currents (ISi) supplied to the probe (PR1; PR2) being in the second state is lower than in the first state, characterized in that the controller is constructed for adjusting the electrical signals (Si) to the electrodes (Ei) such that the generated field distribution (Fi) gradually changes from the first field distribution in the first state into the second field distribution in the second state or the other way around, wherein the total amount of electrical stimulation currents in the tissue is decreased when the field distribution in the tissue is made less symmetrical. in a first state a first distribution of the electrical signals (Si) to the electrodes (Ei) for generating a first field distribution, and in a second state a second distribution of the electrical signals (Si) to the electrodes (Ei) for generating a second field distribution, wherein the first distribution is more symmetrical with respect to the electrodes (Ei) than the second distribution, and the electrical signals (Si) to obtain a sum of electrical stimulation currents (ISi) supplied to the probe (PR1; PR2) being in the second state is lower than in the first state, characterized in that the controller is constructed for adjusting the electrical signals (Si) to the electrodes (Ei) such that the generated field distribution (Fi) gradually changes from the first field distribution in the first state into the second field distribution in the second state or the other way around, wherein the total amount of electrical stimulation currents in the tissue is decreased when the field distribution in the tissue is made less symmetrical.