Did the geometry of the square room control the preferred directions in the distal background condition?
Although rats can ignore landmark cues and instead navigate based on the geometry of the environment (Cheng, 1986; Margules and Gallistel, 1988), it is unlikely that the preferred directions of the HD cells were influenced by the geometry of the square room when the cylindrical enclosure was absent. First, the room geometry has been shown to influence orienting behavior in asymmetric (rectangular) environments. Here, there were no evident differences in the metrics of the four corners or the four walls. If the geometry of the square room was a controlling factor, one would predict that the preferred directions would have rotated by multiples of 90° because of its symmetry. However, in the distal background condition, the HD cells always retained the same preferred directions after the objects were rotated. Were the most distal cues used as reference landmarks for anchoring preferred directions in both conditions? Another possible explanation for the difference in efficacy of the very s
