Techniques for determining the location of a physiological midline are disclosed. A first technique evaluates the response to stimulation of spinal electrodes at peripheral electrodes on different sides of the body. In this technique, a spinal electrode's position relative to a physiological midline is determined based on a relationship between responses to its stimulation observed on different sides of the body. A second technique evaluates the response of spinal electrodes to stimulation of peripheral electrodes on different sides of the body. In this technique, a spinal electrode's position relative to a physiological midline is determined based on the different responses that it observes to stimulation on different sides of the body.
