Evidence for a critical role of entorhinal cortex at pre-exposure for latent inhibition disruption in rats.
Latent inhibition (LI), that is the decrease in conditioned response induced by the repeated nonreinforced pre-exposures to the to-be-conditioned stimulus, is disrupted by entorhinal cortex (EC) lesions. The mechanism involved in this disruption is unknown, and in particular the experimental stage (pre-exposure or conditioning) at which the integrity of EC is necessary has to be determined. The purpose of this study was to address this issue by using reversible inactivation of the EC by local micro-infusion of tetrodotoxin (TTX). TTX was infused either before the pre-exposure phase, before the conditioning phase, or before both phases. LI was unaffected in rats that received TTX before conditioning or before both pre-exposure and conditioning. In contrast, LI was disrupted in rats that received TTX before pre-exposure only. These results are discussed in the framework of LI models.
Seillier
A
A
Laboratoire de Neurosciences Comportementales et Cognitives, FRE 2855, Strasbourg, France.
Dieu
Y
Y
Herbeaux
K
K
Di Scala
G
G
Will
B
B
Majchrzak
M
M
D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D004644:Emotions / Q000187:drug effects / Q000502:physiology; D018728:Entorhinal Cortex / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology
D026941:Sodium Channel Blockers; D015222:Sodium Channels; D013779:Tetrodotoxin