Abstract
Analysis of the neural mechanism of place navigation requires isolation of the landmark dependent allocentric and self-motion related idiothetic orientation modes. To assess their importance, rats were trained on a rotating (360°/min) arena to avoid foot shocks applied in either a room frame defined sector of the arena or an idiothetically defined region of the floor. Independence of the respective allocentric and idiothetic engrams was revealed by simultaneous avoidance of both locations. The possibility that idiothetic orientation was confounded by allocentric intramaze cues was examined in an apparatus consisting of an inner rotating disc surrounded by a stationary belt. As long as the rat was on the moving disc, position of the 60°shock sector was stable on the disk but projected from it to different parts of the belt. When the rat moved to the belt the shock sector was now stable on the belt, but its projection to the disk travelled over its moving surface. The rat always found the shock sector in an idiothetically correct position but the mutual shifts of the disk and belt eliminated the utility of local cues like scent marks for the idiothetic solution of the task. Purely allocentric orientation was required in a place recognition tasks in which pressing a lever mounted on a rotating arena was rewarded only when the operandum moved through an allocentrically defined 60°segment of its trajectory. Place recognition was manifest by increased bar presenting rates on approach to and inside the reward zone. These methods may reveal how hippocampal place cell activity correlates with both allocentric and idiothetic aspects of spatial orientation.
Original language | English (US) |
---|---|
Pages (from-to) | 689-699 |
Number of pages | 11 |
Journal | Neuropharmacology |
Volume | 37 |
Issue number | 4-5 |
DOIs | |
State | Published - Apr 5 1998 |
Keywords
- Hippocampus
- Intramaze cues
- Path integration
- Place avoidance
- Place recognition
- Spatial memory
ASJC Scopus subject areas
- Pharmacology
- Cellular and Molecular Neuroscience