Impairment of spatial but not contextual memory in CaMKII mutant mice with a selective loss of hippocampal ltp in the range of the θ frequency

AbstractWe ssessed hippocampal-dependent memoryin mice with a Ca2+-independent form of CaMKII generated by the introduction of an aspartate at amino acid 286. The CaMKII-Asp-286 mice show normal LTP at high frequency stimulation, but in the 5–10 Hz range, they show a shift in the frequency-response curve favoring LTD. This range of frequencies is similar to the θ rhythm, which is associated with exploration in rodents. Using the Barnes maze to assess spatial memory, we found the transgenic mice could not learn to navigate to a specific location using spatial cues. In contrast, one line of transgenic mice performed normally in contextual fear conditioning, a task that is also hippocampal dependent. This dissociation between spatial and contextual memory suggests that even though both require the hippocampus, they may be mediated by different synaptic mechanisms