Fig. 1

Effects of IFNα on behavioral activity and hippocampal neurogenesis in common marmosets. a: Experimental procedures. Adult common marmosets were treated with human pegylated IFNα or vehicle (control, Cnt) once a week for 4 weeks (see Materials and Methods in supplemental information), and BrdU was injected once a day for the first 10 consecutive days. The voluntary activity of each animal was continuously monitored by actigraphy from the day before (− 1d) treatment to the end of the experimental period. The animal tissues were fixed at day 28 for histological analyses. b: Mean bodyweight of the animals in the control and IFNα-treated groups before (on day − 1) and during drug administration (on day 7, 14, 21, and 28). c-c’: Daytime (c) and nighttime (c’) mean activity counts of animals for 10 days after fitting the actigraphy device. d-d’: Daytime (d) and nighttime (d’) mean activity counts of animals a day before (−1d) and each week during IFNα or vehicle treatment. e-f: Representative images of BrdU-labeled (BrdU+) cells in the SGZ and GCL of the dentate gyrus. The Z-stack projection image shows BrdU+ cells (magenta) expressing Dcx (green) (e). Confocal image showing a BrdU+ cell (red) expressing NeuN (cyan) (f). The x-z and y-z planes are presented in the top and right panels, respectively. g-h: Z-stack projection images of the dentate gyrus immunostained for BrdU (magenta), Dcx (green), and NeuN (blue) in control (g) and IFNα-treated (h) animals. High-magnification images of the boxed areas in (g) and (h) are shown in (g’) and (h’), respectively (BrdU: magenta, Dcx: green, The x-z and y-z planes are presented in the top and right panels, respectively). i: The number of BrdU+ cells that express Dcx or NeuN in the dentate gyrus (SGZ and GCL). Scale bars: 10 μm (e-h’). The quantitative data are presented as the mean ± SEM. *P < 0.05, **P < 0.01