Fast coordination of neuronal activity is necessary for quick and transient synchronization of neuronal ensembles and may be the neural mechanisms for forming representations important for gestalt-like perception. In the medial temporal lobe, gamma activity is a typical feature of activated (waking and REM) states but recently we have found it to be expressed during the Slow Oscillation. One major question that we are asking is: “Does state influence the expression of the networks involved in gamma? (i.e., Are there differences in the generation of this activity across deactivated and activated patterns?)” We are also investigating the local circuit mechanisms important for gamma in the entorhinal cortex. We are interested in what defines the modular arrangement of its expression (Dickson et al 2000) in addition to how synchronization might occur across long distances (Dickson and de Curtis, 2002).