Fig. 1.

Representative double-plotted actograms of wheel-running activity and hormone profiles. Control (blue) and split (red) hamsters were surgically implanted with jugular catheters (arrows), and blood was collected for 24 h (colored horizontal lines on actograms). A, Plasma cortisol of representative control and split hamsters relative to wheel-running activity onset (dotted line). B, Plasma ACTH of representative control and split hamsters relative to wheel-running activity onset (dotted line). Dashed diagonal colored bands expand the 24-h scale on the day of bleeding for better visualization.