Repetitive Acute Intermittent Hypoxia for Spinal Cord Repair

The experiments in this study will test the following: Hypothesis 1.1(Experiment 1) that rAIH will enhance corticospinal excitability and upper and lower limb function in humans with incomplete SCI. Hypothesis 1.2 (Experiment 2) that enhancing the aftereffects of rAIH with exercise training will further enhance upper and lower limb motor function in humans with incomplete SCI. Measurements of corticospinal, cortical, and motoneuron excitability will be tested to further understand the mechanisms of this induced-plasticity. Persons with chronic (\>6 months) spinal cord injury between the levels of C2 and T2. SCI subjects must possess either the ability to produce a visible precision grip force with one hand, and/or the ability to perform some small wrist flexion and extension. Additionally, subject must possess the ability to perform a small visible contraction with dorsiflexion and hip flexor muscles. Controls must be right handed due to potential differences in the organization of the brain in right handed and left handed individuals.