The hippocampus plays an important role in eyeblink conditioning with a short trace interval in glutamate receptor subunit delta 2 mutant mice.
Mutant mice lacking the glutamate receptor subunit delta2 exhibit changes in the structure and function of the cerebellar cortex. The most prominent functional feature is a deficiency in the long-term depression (LTD) at parallel fiber-Purkinje cell synapses. These mutant mice exhibit severe impairment during delay eyeblink conditioning but learn normally during trace eyeblink conditioning without the cerebellar LTD, even with a 0 trace interval. We investigated the hippocampal contribution to this cerebellar LTD-independent "0 trace interval" learning. The mutant mice whose dorsal hippocampi were aspirated exhibited severe impairment in learning, whereas those that received post-training hippocampal lesions retained the memory. The wild-type mice showed no impairment in either case. These results suggest that the hippocampal component of the eyeblink conditioning task becomes dominant when cerebellar LTD is impaired.
Takatsuki
Kanako
K
Laboratory of Neurobiophysics, School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
Kawahara
Shigenori
S
Kotani
Sadaharu
S
Fukunaga
Satoshi
S
Mori
Hisashi
H
Mishina
Masayoshi
M
Kirino
Yutaka
Y
D000818:Animals; D001522:Behavior, Animal; D001767:Blinking; D002525:Cerebellar Cortex / Q000502:physiology; D003215:Conditioning, Eyelid; D006624:Hippocampus / Q000033:anatomy & histology / Q000502:physiology*; D007700:Kinetics; D007858:Learning; D036881:Long-Term Synaptic Depression; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D017470:Receptors, Glutamate / Q000235:genetics*
D017470:Receptors, Glutamate; C107913:glutamate receptor delta 2