Figure 2.

β1-integrins in the developing OFC are necessary for expectancy updating. Experimental timelines are shown at the top of each row. A, In a fear conditioning procedure, freezing increased with repeated tone–shock pairings. When exposed to conditioned stimuli in the absence of foot shock (extinction), Itgb1 knock-down mice froze more, a failure in fear extinction. Exaggerated freezing was again detected the following day, indicated by a break in the x-axis (n = 8 control, 9 knock-down). B, Locomotor activity did not differ between groups. C, Separate mice were trained to respond equivalently on two nose poke apertures for food reinforcers. Response rates represent both responses/min. D, After training, the likelihood of reinforcement associated with one nose poke response was reduced (degraded). Itgb1 knock-down mice failed to differentiate between responses, failing to update outcome expectancies (n = 9 control, n = 9 knock-down). E, We focused the rest of our report on reward-related responding, first replicating our experiments using lentiviral-mediated gene silencing. Mice were trained to respond on two nose poke apertures for food reinforcers. F, When the likelihood of reinforcement associated with one nose poke response was reduced (degraded), again, Itgb1 knock-down mice failed to differentiate between familiar responses (n = 7 control, 13 knock-down). G, Groups did not differ, however, when auditory and visual stimuli signaled reinforcer delivery. In this condition, both groups readily differentiated between reinforced and nonreinforced (“inactive”) behaviors. H, I, When viral vectors were delayed until P31, no effects on response training (H) or action–outcome conditioning (I) were detected (n = 5 control, n = 4 knock-down). Data are shown as means + SEM, except gray symbols represent individual mice. *p < 0.05, **p = 0.005 main effect of response choice, with no interactions. n.s., Nonsignificant. Experiments were conducted at least twice. Illustration credit: A. Allen.