The uncertainty of it all.

The amygdala is clearly implicated in the processing of biologically relevant stimuli, particularly those that can lead to a state of fear. A new study by Herry, Bach and colleagues using both mouse and human subjects seemingly throws a wrench in the spokes by demonstrating that the amygdala is sensitive to non-biologically relevant stimuli (i.e. tones) when they occur in an unpredictable fashion. The implications of this finding for understanding the role of the amygdala in vigilance, threat assessment and anxiety are considered here.