Abstract
Spinal cord function plays a critical regulatory role in homeostasis, cardiovascular responsivity, sensation, and movement. The spinal cord houses contains connection networks that interact with the brain and brainstem, cerebellum, and peripheral nervous system. Normal function requires several levels of feedback control, filtering, and modulation. Control systems operate based on precise anatomical locations, normative set-points, functional connections, feedback regulated firing rates, and balanced excitation and inhibition. When these are altered by interruption and denervation after spinal cord injury (SCI), there may be severe consequences across the acute, subacute, and chronic phases of the injury. The magnitude and severity of disrupted feedback are generally proportional to the neurological level and completeness of injury. Well-known post-SCI problems include blood pressure (BP) dysregulation, cardiovascular dysfunction, autonomic dysreflexia (AD), neuropathic pain, spasticity, and abnormal thermal regulation. These primarily arise from deafferentation neuroplasticity and inappropriate excitation-inhibition balance. In this review, we approach these problems from the perspective of feedback disruption and illustrate how understanding the control circuits provides access points for therapies.