Representative Training Schedule. Rats were tested daily, Monday through Friday. In order to be eligible for stress testing, three criteria must be met: 1) The animal must have achieved a score of 6, 7 or 8 (out of 10) for at least two consutive days; 2) at least one week must have passed since the last stress exposure; 3) females must be cycling regularly on a 4–5 day cycle, and it must be anticipated that they will be in either proestrus or estrus on stress day. In this figure, the rat is ready for testing on the first Wednesday because her two previous scores are 7 and 8, and she will be in estrus. In the sond week, she does not receive stress treatment because her scores do not qualify her on a day when she will be in estrus or proestrus. In the third week, her scores on Tuesday and Wednesday qualify her for treatment on Thursday, and she will be in proestrus, so she receives treatment. In week four, her scores and cycle qualify her for treatment on Friday.