Figure 4. Anesthetic effects on relearning odor associations.

(A) Percentage of time spent smelling a two-odor mixture (Odor AB) and one of the components (designated as Odor B), along with two background beads, during the first recognition test shown in Fig. 1. Odor mixture was previously exposed under awake (cyan) and propofol-anesthetized (red) conditions. Alternating components were used as Odor B in a counter-balanced design among different animals (n = 6). (B) Percentage of smelling time on the mixture (Odor AB) and one of the components (Odor B) during the second recognition test shown in Fig. 1, after animals consciously relearned the mixture along with one of the components. (C) Correspondence analysis of the discretized data from (B). Color scheme is the same as in (A,B). Solid and open circles are Odor AB and Odor B, respectively, and solid and open squares are Background A and B, respectively. (D) The delta ratios were calculated from (B) as (Odor AB − Odor B)/(Total Smelling Time). When the mixture was first learned under propofol anesthesia and relearned consciously with one of the components, the animals exhibited a memory deficit in recognizing the component but not the mixture. The same statistical method and presentation as in Fig. 3 are used.