A, B, D, E: Images showing NPY expression in DMH, IH and IN in day (A, B) and night (D, E) during non-migratory (A, D) and migratory states (B, E). Also shown are NPY-lir cell numbers (mean ± SD, C, F), percent NPY-lir cell area (per grid area, 26, 250 µm2; G, I) and mean cell optical density (cell OD; H, J) in day (C, G, H) or night (F, I, J). K: Schematic illustration of different MBH subdivisions. Asterisk (*) indicates the significance of difference at p<0.05 level. Scale bar: general views = 200 µm (A, B, D, E); schematic (K) = 500 µm; magnified views (i - DMH; ii - IH; iii - IN) = 25 µm. Abbreviations: 3V, third ventricle; DMH, dorsomedial hypothalamus; IH, inferior hypothalamic nucleus; IN, infundibular nucleus; ME, median eminence; SMD, supramamillary decussation; TrO, optic tract.