Methods for studying habitual behavior in mice

Abstract

Habit formation refers to the process by which goal-directed behavior becomes automatized and less sensitive to changes in the value of the goal. It has clear relevance for our understanding of skill learning and addiction. Recent studies have begun to reveal the neural substrates underlying this process. This unit summarizes what is known about the experimental methods used, and provides a protocol for generating and assessing habit formation in mice.

Figure 1

Each operant chamber (21.6 cm long × 17.8 cm wide × 12.7 cm high) should be housed within a light-resistant and sound-attenuating box. Each chamber has a pellet receptacle in the center of one wall where food pellets are dispensed via an external pellet dispenser. On either side of the receptacle are retractable levers, and on the opposite wall, a 3 W, 24 V house light.

Figure 2

Example of a mouse performing on an operant task.

Figure 3

Data from a devaluation test adapted from a published study (Yu et al., 2009). WT, wild-type mice; KO, A2A adenosine receptor knockout mice.