Design a comprehensive experimental study to investigate the relationship between sleep patterns, cognitive performance, and neuroplasticity in adults aged 25-45. Your design must address: 1) appropriate control and experimental groups, 2) measurement of relevant variables including both subjective and objective metrics, 3) consideration of confounding variables and how to control for them, 4) statistical analysis plan, 5) ethical considerations, and 6) potential limitations and how to mitigate them. Include a detailed hypothesis and justify all methodological choices with references to current scientific literature.