Reevaluating the role of the hippocampus in delay eyeblink conditioning.
The role of the hippocampus in delay eyeblink conditioning (DEC) remains controversial. Here, we investigated the involvement of the hippocampus in DEC with a soft tone as the conditioned stimulus (CS) by using electrolytic lesions or muscimol inactivation of guinea pig dorsal hippocampus. Interestingly, when a soft tone was used as a CS, electrolytic lesions of the hippocampus significantly retarded acquisition of the conditioned response (CR), and muscimol infusions into hippocampus distinctly inhibited the acquisition and expression of CR, but had no significant effect on consolidation of well-learned CR. In contrast, both electrolytic lesions and muscimol inactivation of hippocampus produced no significant deficits in the CR when a loud tone was used as the CS. These results demonstrate that the hippocampus is essential for the DEC when the delay task was rendered more difficult.
Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.
Guang-yan
GY
Wu
Juan
J
Yao
Bo
B
Hu
Hui-ming
HM
Zhang
Yi-ding
YD
Li
Xuan
X
Li
Qiong
Q
Li
Jian-feng
JF
Sui
D000818:Animals; D001522:Behavior, Animal; D001767:Blinking / Q000187:drug effects / Q000502:physiology*; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D003215:Conditioning, Eyelid / Q000187:drug effects / Q000502:physiology*; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D046709:Pattern Recognition, Physiological; D013238:Stereotaxic Techniques
D018755:GABA Agonists; D009118:Muscimol