The habituation process may involve generalized reductions in activation of sensory signaling pathways. For example, repeated exposure causes marked reduction in restraint induced c-fos mRNA activation of primary sensory cortices and thalamic sensory relays (in addition to the PVN and limbic stress circuits), suggesting that habituation may be in part due to reduced strength or salience of perceived sensory cues (Girotti et al., 2006).
