In mammals and birds, the hippocampus is a major learning and memory center
that plays a prominent role in spatial memory, the use of distal cues to g
uide navigation. The role of reptilian hippocampal homologues, the medial a
nd dorsal cortex, in spatial memory has not been thoroughly investigated. T
he medial and dorsal cortex of reptiles is known to play a role in learning
both tasks that are hippocampally dependent and tasks that are not hippoca
mpally dependent in mammals and birds. In order to examine the specific rul
e of the medial and dorsal cortex in spatial memory, we trained medial cort
ex, dorsal cortex, and sham lesioned Cnemidophorus inornatus lizards to loc
ate the one heated rock of four identical rocks spaced evenly around the pe
rimeter of a circular, sand filled, arena in a cool room. We used probe tri
als to examine the strategies used by lizards to locate the goal. Medial co
rtex lesions and dorsal cortex lesions slowed acquisition and altered the s
trategies used to locate the goal. However, none of the lizards adopted a s
patial strategy to locate the goal suggesting that the dorsal cortex and me
dial cortex are involved in using non-spatial strategies for navigation. (C
) 2001 Elsevier Science B.V. All rights reserved.