Figure 5.

LC stimulation prior to an episode results in a β-adrenoceptor–dependent enhancement of spatial memory for that particular episode. (A) Schematic summary of the experimental design for the episodic-like memory task. (B) In control experiments, during the Test Episode, rats preferred exploring old displaced objects (A2) over old stationary objects (A1). They showed no spatial preference in the exploration of the more recently seen objects (B1 vs. B2) (n = 22). In experiments in which rats received LC stimulation prior to Episode B, there was a distinct exploration preference for the new displaced object (B2) over the new stationary object (B1) (n = 22). (C) Vehicle (NaCl 0.9%) injected i.c.v. 25 min prior to Episode B did not alter the rats exploration pattern during the Test Episode (n = 17). Vehicle was also injected 25 min prior to LC stimulation and Episode B. The rats again exhibited a preference for the displaced B2 objects over the stationary B1 objects (n = 17). When the β-adrenoceptor antagonist propranolol (2 μg) was injected i.c.v. prior to LC stimulation and Episode B, the preference for B2 over B1 was blocked leaving the preference for A2 over A1 intact (n = 17). Error bars indicate SEM. *P < 0.05, ***P < 0.001.