Figure 1.

CPP design and timeline

(A) Octopus bocki in the start chamber of the CPP box.

(B) Diagram of the apparatus, with pattern shown on the back and sides only for clarity. In experimental trials, visual cues covered all four walls.

(C) Timeline of an experiment showing sequences for CPA and CPP procedures. In this example, an octopus showed an initial preference in session 1 for the dot chamber and is thus trained against initial preference (i.e., the octopus is given AA injection prior to confinement in the dot chamber or lidocaine prior to the stripe chamber). Different animals were used to test each of the four conditions (see Figure 2). Control sequences (saline/saline and saline/lidocaine) not shown.