Formation of long-term memory without short-term memory by CaMKII inhibition

Most of the current models of long-term memory consolidation require prior establishment of short-term memory. Here, we show that optogenetic or genetic inhibition of CaMKII, a kinase important for synaptic plasticity, in an inhibitory avoidance task impairs short-term memory at 1 h but not long-term memory at 1 d. Similarly, cortico-amygdala synaptic potentiation was more sensitive to CaMKII inhibition at 1 h but not at 1 d. These results strongly suggest that long-term memory does not require the prior formation of short-term memory and that CaMKII-dependent synaptic plasticity specifically regulates short-term memory, but not long-term memory, for avoidance memory.