Figure 6. Timeline of the experimental sequence of the short food addiction mouse model.

In the 1^st week, mice are trained to acquire the operant conditioning maintained by chocolate-flavored pellets under FR1 (2 sessions) and FR5 (3 sessions) schedule of reinforcement followed by the surgery for injecting the viral vector of interest (2^nd week). After surgery, the expression of the viral vector is allowed for a period of 4 weeks (2^nd, 3^rd, 4^th, and the 5^th week). At the beginning of this period (3^rd week), mice are under FR5 (4 sessions) to recover the basal levels of operant responding, and at the end of this period (5^th week), an osmotic minipump filled with CNO is implanted. During the 6^th, 7^th, 8^th, and 9^th weeks, when it is a chronic inhibition of the CNO-induced activation of the expressed DREADD receptors, mice are under FR5 scheduled sessions followed by the measurement of the 3 addiction-like criteria.