1. A method for providing an electrical neurostimulation therapy to a neural structure of a patient's body using an implantable medical device (IMD), comprising: providing a first electrical signal using said implantable medical device; applying said first electrical signal to said neural structure, wherein the first electrical signal generates a response that comprises at least one of an afferent action potential or an afferent sub-threshold depolarization; sensing a physiological parameter using an implanted sensor, wherein said physiological parameter includes at least one of a neurotransmitter parameter, a neurotransmitter breakdown product parameter, a neuropeptide parameter, or a glucocorticoid (GC) parameter; modifying said first electrical signal based upon said sensed physiological parameter to generate a second electrical signal; and applying said second electrical signal to said neural structure, wherein the second electrical signal generates a response that comprises at least one of the afferent action potential or the afferent sub-threshold depolarization.