Changes in sleep patterns in mice after sleep fragmentation (SF). (A) Changes in mean sleep latency after 15 days of sleep fragmentation in 57BL6/J and tumor necrosis factor receptor (TNFR) knockout mice when compared with corresponding controls (n = 6;P <0.001). (B) Changes in mean slow wave sleep latency during the circadian cycle in mice exposed to SF for 15 days (open circles) and treated with vehicle (grey line) or TNF-α neutralizing antibodies (dotted line) and mice under control sleep conditions. (*P <0.01; n = 7/group). (C) Increases in theta frequency during quiet waking in C57BL/6 J mice, indicating = increased sleepiness after SF. (D) Mean latencies (seconds)and path lengths (cm) to locate the target platform during (a, b) place training, (c, d) reference memory after training, and (e, f) immobility in the forced swim test in C57BL6/J and TNFR knockout mice exposed to SF or control sleep conditions (*P <0.01; n = 12/group). (E) Mean latencies(seconds) and path lengths (cm) to locate the target platform during place training in mice exposed to SF or control sleep conditions, and treated with vehicle or TNF-α neutralizing antibodies. (*P <0.01; n = 12/group).