s, vol 18, part 1). Rose and Smith are currently applying NMDA 8 antagonists to the rat's hippocampus to see how it effects the rat's ability to navigate a water maze. In particular, they are looking to see if administering NMDA antagonists solely during the REM windows retards place learning. Bramham, Maho, Yonekawa and Laroche applied high frequency stimulation to the perforant pathway of trained rats either in a still alert state (SAL) or during an "enhanced" REM state (it was enhanced as a result of the learning task). They found that tetanisation only induced LTP when applied during the REM state. In control animals, who had not been trained on the task, tetanisation in both SAL and REM induced LTP. They conclude "that avoidance learning affects subsequent LTP induction in a state-dependent manner, allowing normal induction during post-trial REM but suppressing it during wakefulness". 5.3 Neuronal firing patterns during sleep By examining not just the mean firing rate, but als..