It is well known that there are changes in brain rhythms in those who have schizophrenia (SZ). However, the mechanistic causes of those changes and the functional consequences of them are far less understood. In this talk, I will discuss a few case histories to emphasize the subtlety of the changes, with potentially very large functional consequences. These will include effects on network behavior of changes in NMDA receptor function and change in cholinergic activation. The examples all concern changes in SZ to the activity of various classes of interneurons.