"There still remains, however, one unresolved and very controversial issue:
To what extent does long-term potentiation participate in learning and
memory acquisition? Contrary to their expectations, the scientists from
Heidelberg could not demonstrate abnormal learning behaviour in the mutant
mice. Rather, the mice lacking LTP were, like normal mice, capable of
accurately finding a submerged, invisible platform in a pool of murky water
("water maze") and to swim there immediately when placed in the water."
http://www.eurekalert.org/releases/mpg-dal060299.html