Table 1.

A representative day in the modified chronic mild stress protocol.

Experimental group	Stressor session (time of day)
	Morning (9:30–13:00 h)	Afternoon (13:15–16:45 h)	Evening (17:00–20:30 h)
Dispersed	Wet cage	Strobe light	Noise stress
Clustered (1/3)	Wet cage + strobe light + noise stress
Clustered (1/3)		Wet cage + strobe light + noise stress
Clustered (1/3)			Wet cage + strobe light + noise stress

Each day, Dispersed and Clustered rats were exposed to three acute stressors during 1, 2, or 3 blocks of time (morning, afternoon, and evening). Lights in the colony and procedure rooms were off from 09:00 to 21:00 h, thus, morning sessions occurred at the beginning of the dark/active phase, and evening sessions at the end of the dark/active phase. Rats in the Dispersed groups received one stressor per session; rats in the Clustered group received all three stressors within one of the three sessions. In the Clustered group, to control for time of day, one-third of this group received all three stressors in the morning, one-third during the afternoon, and one-third during the evening. Within this group, each rat received stressors during an equal number of morning, afternoon, and evening sessions across the 4 weeks of chronic mild stress.