Pharmacological experiments show a decrease of olfactory memory duration after α1 receptor blockade. The graph shows acquisition (trials 1–20) of the odor–reward association during local pharmacological blockade of NE receptors in the OB (no blockade, α1, α2, β, or all receptors blocked) and 24 recall with no receptor blockade. Note that mice with α1 or all receptors blocked showed significantly longer delays for recall after 24 h than saline controls, showing that NE effects on long-term memory are mediated at least partially by α1 receptor activation. Data are available in Extended Data Figure 2-1.