It should be noted, that the effects reported here could be demonstrated even though the chemosensory stimuli were applied repeatedly (200 times) and with relatively short ISIs (9s) in each EEG session. Repeated odor stimulation would result in a strong habituation and thus a strong reduction of the CSERP amplitudes [28], [54]. However, recent research indicates that chemosensory alarm signals are not processed in olfactory, but in separate sensory systems [8], [10]. Accordingly, it has been reported that the response to social chemosignals is less prone to effects of habituation than the response to common odors [55]. For example, rodents respond to a continuous exposure to chemosensory alarm signals of consepecifics with a 40 min lasting autonomic stress response (increase in body temperature [56]).
