The invention relates to an apparatus for stimulating neurons having a pathological synchronous and oscillatory neural activity, the apparatus including a stimulation unit having a plurality of stimulation contacts to stimulate neurons in a patients brain and/or spinal cord with electric stimuli, a measurement unit for recording test signals that represent a neural activity of the stimulated neurons, and a control and analysis unit. Furthermore, the stimulation contacts of the stimulation unit apply stimuli, and the control and analysis unit selects the stimulation contacts, the stimuli of which cause the phase of the pathological synchronous and oscillatory neural activity of the stimulated neurons to be reset. The selected stimulation contacts then apply phase-resetting stimuli with a time delay, and the control and analysis unit verifies whether the pathological synchronous and oscillatory neural activity of the stimulated neurons is suppressed by said time-delayed stimuli.