Figure 1.

Delayed-match-to-sample radial water maze task. Each day (Day x, Session x) rats were given one forced-choice sample trial, with access to all but the start (S₁) and goal (G) arm blocked. The goal arm contained a submerged platform. On the test trial (typically 1 h later), all arms were open and a different start (S₂) arm was used to test memory for the spatial location of the current goal location. Typically only one sample and one test trial were given each day. Solid lines depict path to goal. The most common first errors are depicted in Test Trial on Day x + 1, Session x + 1. Once rats are well trained, the majority of first errors are to one of the arms on either side of the goal (adjacent; dashed line) or to the previous goal arm.