The entorhinal cortex, but not the dorsal hippocampus, is necessary for single-cue latent learning.
Two experiments were conducted to examine the roles of the entorhinal cortex (EC), dorsal hippocampus (DH), and ventral hippocampus (VH) in a modified Latent Cue Preference (LCP) task. The modified LCP task utilized one visual cue in each compartment, compared to several multimodal cues used in a previous version. In the single-cue LCP task, water-replete rats drink water in one compartment of the LCP box on 1 day, and then have no water in a second compartment of the LCP box the following day (one training trial), for a total of three training trials. Rats are then water-deprived prior to a preference test, in which they are allowed to move freely between the two compartments with the water removed. Latent learning is demonstrated when water-deprived rats spend more time in the compartment that previously contained the water. Experiment 1 demonstrated that the single-cue LCP task results in the same irrelevant-incentive latent learning as the multicue LCP task. In addition, Experiment 1 replicated the finding that a compartment preference based on this latent learning requires a deprivation state during the preference test, while a compartment preference based on conditioning does not. Experiment 2 examined the effects of pretraining neurotoxin lesions of the EC, DH, and VH on this single-cue LCP task. Results showed that lesions of the EC and VH disrupted the irrelevant-incentive latent learning, while lesions of the DH did not. These results indicate that a latent learning task that involves one discrete compartment cue, rather than several compartmental cues, does not require the DH. Therefore, the EC appears to play a central role in single-cue latent learning in the LCP task.
Stouffer
Eric M
EM
Department of Psychology, Bloomsburg University of Pennsylvania, Bloomsburg, Pennsylvania, USA. estouffe@bloomu.edu
D000818:Animals; D003463:Cues; D018728:Entorhinal Cortex / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology