Figure 6.

Comparison of pre-pulse (A) and Gap (B) inhibition of the acoustic startle reflex (ASR) in mice at 5-7 months (15 mice), 22-24 months (based on 18 of the 26 mice, 8 that did not jump are not included) or 27-29 months (based on 13 mice – 9 mice that did not jump are not included) of age. At 5-7 months of age both the pre-pulse and the gap produce a mean inhibition of the ASR of 30-35%. At 22-24 months of age there is no longer a significant gap-inhibition of the ASR while the pre-pulse inhibition remains in the 30-35% range. The difference in Gap Detection between 5-7 months, 22-24, and 27-29 months is significant (p< 0.01), while pre-pulse inhibition has not changed, indicating an age-related decrease in gap detection. At 27-29 months of age there is no longer a significant pre-pulse or gap inhibition of the ASR, indicative of the large hearing loss in many animals. Asterisks indicate significance (p<0.01). Significance was tested using the Student t test (Sigmaplot)