Allegoric depiction of fear masking in amygdala. One group of nerve cells in the brain controls the fear behaviour (right). This can be suppressed by a second group of nerve cells (left) – but the fear is only masked, and has not disappeared completely. Slightly modified version of illustration used for: Vlachos I, Herry C, Lüthi A, Aertsen A and Kumar A (2011) Context-Dependent Encoding of Fear and Extinction Memories in a Large-Scale Network Model of the Basal Amygdala. PLoS Comput Biol 7(3): e1001104. doi:10.1371/journal.pcbi.1001104