Figure 1.
Experiment 1: Rats anticipate scheduled daytime mating with food and a running wheel continuously available.
Panels A–B. Actograms of home cage motion (A} and wheel running (B} of a representative rat. Each line represents one day of recording, plotted in 10 minute bins from left to right, with consecutive days aligned vertically. Bins in which activity counts were registered are represented by heavy bars (in quartile weights}. Daily scheduled mating time is indicated by the vertical opaque bar outlined in red. Lights-off is indicated by grey shading. The triangles in panel B denote the 48 h during which the rats were confined to their mating cage to gain sexual experience. The home cage motion sensors could detect activity in some parts of the mating cage. Panels C–D. Group mean waveforms of home cage motion (C} and wheel running (D}, averaged over 5 baseline days (shaded curve, from days indicated by the upper bracket to the left of panels A and B} and 10 scheduled mating days (heavy blue curve, from days indicated by the lower bracket to left of panels A and B}. Zeitgeber time refers to the hour of the LD cycle (lights-off from ZT12-24}. Mate access time (ZT6-7} is denoted by the vertical bar (red dotted bars}.
Figure 2.
Experiment 2: Most rats fail to anticipate daytime mating when post-coital eating and wheel running are prevented for 6 or 10 h.
Panels A–C. Actograms of home cage motion (A}, mating tube entry (B} and wheel running (C} of a representative rat. Panels D–F. Group mean waveforms of the 5 of 6 rats in Group 1 that showed little (N = 1} or no (N = 4} sex anticipatory activity in home cage motion (D}, mating tube entry (E} and wheel running (F}. The filled (grey} curve represents baseline prior to scheduled mating (the average of the days marked by the upper black bracket to the left of each actogram in Panels A–C}. The heavy (blue} curve represents scheduled mating days 51–60 (the middle blue brackets in A–C, when running wheels were locked from ZT6-12, and food was available from ZT12-24}. The green curve represents days 71–80 (the lower green brackets in A–C, when running wheels were locked from ZT6-16, and food was available from ZT16-24}. The time of food availability is indicated by the horizontal blue (ZT12-24} and green (ZT16-24} bars at the top of panels D–F. See Figure 1 for other plotting conventions.
Figure 3.
Experiment 2: One rat (Group 1, rat#3} eventually shows anticipatory activity to scheduled mating, with post-coital eating and wheel running blocked.
Panels A–C. Actograms of home cage motion (A}, mating tube entry (B} and wheel running (C} in rat #3. Panels D–F. Average waveforms of activity in home cage motion (D}, mating tube entry (E} and wheel running (F} in rat#3. See Figure 2 for other plotting conventions.
Figure 4.
Experiment 2: Rats exposed only to sight, sound and smell of estrous females do not exhibit anticipatory activity.
Group average waveforms: Panels A–C, home cage motion, mating cage access tube and running wheel activity, respectively, in Group 2 rats (n = 6}. Panel D, home cage motion in Group 3 rats (N = 6}. The shaded curves represent baseline prior to scheduled daily exposure to estrous females. The heavy (blue} curves represent scheduled exposure days 51–60. The green curves represent days 71–80. See Figure 2D–F for other plotting conventions.
Figure 5.
Experiment 3: Rats anticipate both late night (ZT21} and midday (ZT6} scheduled mating when provided access to a single female for a full hour to increase ejaculation rates.
Each actogram represents total activity (the sum of activity counts registered by the overhead motion sensor and the two tube sensors} in 6 of 8 rats (A–F, corresponding to rats 1–6 in Figure S3}. The daily mating hour is denoted by the opaque vertical bars outlined in red. See Figure 1 for other plotting conventions.
Figure 6.
Experiment 3: Group mean (±sem} waveforms illustrating anticipatory activity in response to scheduled mating.
A. Baseline week, no scheduled mating. B. Week 4, late night mating (ZT21}. C. Week 4, daytime mating (ZT6}. D. Day 2 of constant dark without scheduled mating, after the daytime mating schedule. The black curve represents activity detected by the overhead motion sensor. The purple curve (with error bars below} represents activity in the tube to the locked cage. The red curve (with error bars above} represents activity in the tube to the mating cage. Scheduled mealtime is denoted by the opaque vertical bars with dashed red borders. The time of food availability is indicated by the heavy blue line at the top of each figure.
Figure 7.
Experiment 3: Group mean (±sem} mating anticipation ratios.
The ratios were calculated by dividing activity during the 3 h prior to the mating hour by total daily activity, excluding the mating hour and the 2 h immediately following. Stars denote significantly different from baseline for that activity measure (p<.05}. Ratios for activity in the tube to the mating cage were significantly different from ratios for activity in the tube to the locked cage in the ZT21 mating condition (red dashed line}, but not in the ZT6 mating condition.