RESTRICTED AND REGULATED OVEREXPRESSION REVEALS CALCINEURIN AS A KEY COMPONENT IN THE TRANSITION FROM SHORT-TERM TO LONG-TERM-MEMORY

To investigate the roles phosphatases play in hippocampal-dependent me mory, we studied transgenic mice overexpressing a truncated form of ca lcineurin. These mice have normal short-term memory but defective long -term memory evident on both a spatial task and on a visual recognitio n task, providing genetic evidence for the role of the rodent hippocam pus in spatial and nonspatial memory. The defect in longterm memory co uld be fully rescued by increasing the number of training trials, sugg esting that the mice have the capacity for long-term memory. We next a nalyzed mice overexpressing calcineurin in a regulated manner and foun d the memory defect is reversible and not due to a developmental abnor mality. Our behavioral results suggest that calcineurin has a role in the transition from short-to long-term memory, which correlates with a novel intermediate phase of LTP.