Brain Chemical May Mediate Bad Memories

The investigators examined the association between foot shock and auditory tone in mice bred without CB1 antagonist SR141716A. The mice were first conditioned to associate the shock with the tone, which induced a freezing behavior. Later, when just the tone was played, both groups of mice froze. Over the next 12 days, the mice without CB1 continued to freeze when the tone was played, while the wild-type mice gradually decreased the freezing behavior. Beat Lutz, Ph.D., one of the study authors, explained to the press that this finding could lead to new treatments for posttraumatic stress disorder and other anxiety disorders