Figure 7.

Maximum startle response to a 95-, 110-, or 125-dB stimulus in mice aged 4 (n = 24), 12 (n = 27), and 18 (n = 28) months. Young mice produce larger startle responses to louder stimuli. This is not necessarily true for older mice. Although 12-month-old mice show strong reactions to the three dB levels, there is no difference between these reactions. Mice aged 18 months produce small startle responses to 95- and 110-dB stimuli, but a significant increase in startle is not observed until the loudest stimulus is presented.