Hippocampal lesions disrupt navigation based on cognitive maps but not heading vectors.
Animals can find a hidden goal in several ways. They might use a cognitive map that encodes information about the geometric relationship between the goal and two or more landmarks. Alternatively, they might use a heading vector that specifies the direction and distance of the goal from a single landmark. Rats with damage to the hippocampus have difficulty in finding a hidden goal. Here we determine which of the above strategies is affected by such damage. Rats were required to swim in a water maze to a submerged platform, which was always at the same distance and direction from a landmark. The platform and landmark remained in the same place for the four trials of each session, but they were moved to a new position at the start of a session. Rats with damage to the hippocampus found the platform more efficiently than did normal rats in the first trial of a session but, in contrast to normal rats, their performance did not improve during a session. Our results indicate that hippocampally damaged rats are able to navigate by means of heading vectors but not cognitive maps.
Pearce
J M
JM
School of Psychology, Cardiff University, UK. pearcejm@cardiff.ac.uk
Roberts
A D
AD
Good
M
M
D000818:Animals; D003071:Cognition / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology* / Q000503:physiopathology; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D051381:Rats; D013550:Swimming