The role of extramaze cues in spontaneous alternation in a plus-maze.

Performance on various spatial tasks is superior in the presence of extramaze cues that provide guidance in locating the goal. This study was an investigation of the effect of such cues on nonrewarded, continuous spontaneous alternation in a plus-maze, a spatial task with no explicit reinforcement. Rats were tested in five daily sessions. Alternation scores, which reflect how frequently the least recently visited arms are chosen, were calculated for each day. On the first day only, rats in the stimulus-rich condition, with cues added to the curtain that surrounded the maze, alternated more than did rats in the stimulus-poor condition. Over days, the stimulus-rich group showed a significant downward trend in alternation, whereas the stimulus-poor group showed an upward trend, but all the groups always alternated at levels greater than chance. Thus, although performance on this task can be enhanced by the presence of extramaze cues, other types of information support alternation.