Measurement of locomotor activity. Histograms of active (top) and quiet (bottom) bout duration in peripherin heterozygotic (Hz) and homozygotic (H) mice. Locomotor activity data were collected at 1 minute intervals. Each minute with LMA larger than 6 counts was defined as being active, and the rest were defined as being quiet. A bout was defined as a period during which a state presented consecutively without interruption of the other. For equal bin histograms (left), the active bout data are binned in 4-minute intervals, and the quiet bout data are binned in 1-minute intervals. The solid lines with white circles represent group averages of the Hz mice and the solid lines with black circles represent group averages of the H mice. The bar graphs (right) show the differences between the Hz and H mice in three arbitrary bins of bout duration. The white bars represent the Hz mice and the black bars represent the H mice. A similar analysis of LMA in 8 hypocretin-ataxin mice versus 8 control littermates was effective in predicting sleep/wake fragmentation hypocretin-ataxin mice (see text).