Learning strategy selection in the water maze and hippocampal CREB phosphorylation differ in two inbred strains of mice.
Learning strategy selection was assessed in two different inbred strains of mice, C57BL/6 and DBA/2, which are used for developing genetically modified mouse models. Male mice received a training protocol in a water maze using alternating blocks of visible and hidden platform trials, during which mice escaped to a single location. After training, mice were required to choose between the spatial location where the platform had been during training (a place strategy) and a visible platform presented in a new location (a cued/response strategy). Both strains of mice had similar escape performance on the visible and hidden platform trials during training. However, in the strategy preference test, C57BL/6 mice selected a place strategy significantly more often than DBA/2 mice. Because much evidence implicates the hippocampus and striatum as important neural substrates for spatial/place and cued/response learning, respectively, the engagement of the hippocampus was then assessed after either place or cue training by determining levels of cAMP response element-binding protein (CREB) and phosphorylated CREB (pCREB) in these two mouse strains. Results revealed that hippocampal CREB levels in both strains of mice were significantly increased after place in comparison to cued training. However, the relation of hippocampal pCREB levels to training was strain dependent; pCREB was significantly higher in C57BL/6 mice than in DBA/2 mice after place training, while hippocampal pCREB levels did not differ between strains after cued training. These findings indicate that pCREB, specifically associated with place/spatial training, is closely tied to differences in spatial/place strategy preference between C57BL/6 and DBA/2 mice.
Sung
Jin-Young
JY
Graduate Program in Neuroscience & Institute for Brain Science and Technology (IBST), Inje University, Daejeon 305-804, South Korea.
Goo
June-Seo
JS
Lee
Dong-Eun
DE
Jin
Da-Qing
DQ
Bizon
Jennifer L
JL
Gallagher
Michela
M
Han
Jung-Soo
JS
D000818:Animals; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D010766:Phosphorylation; D013028:Space Perception / Q000502:physiology*; D013045:Species Specificity; D013550:Swimming
C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein