Top: Baseline von Frey thresholds were assessed 3 days prior to surgery and then at 5–7 day intervals starting on day 2 and continuing until the resolution of mechanical hypersensitivity at day 35 (Pre-CPP). The CPP assay began on day 36 with acclimation to the chambers (Familiarization), followed by two days of preconditioning, three days of conditioning, and then testing on day 42. Bottom: The CPP apparatus consisted of 3 chambers: (left) a chamber with horizontal wall paper, smooth or textured flooring (depending on counterbalancing assignment), and 20% light intensity; (center) a chamber with grey wall paper, grated bar flooring, and 100% light intensity; (right) a chamber with vertical wall paper, smooth or textured flooring (depending on counterbalancing assignment), and 20% light intensity.