title: Aging effects on the startle response and startle plasticity in Fischer F344 rats.
abstract: The effects of aging on acoustic and airpuff startle reactivity, acoustic and airpuff startle habituation, acoustic and cross-modal (light-acoustic) prepulse inhibition (PPI), and fear-potentiated startle (FPS) were examined using 3- (Y: young), 11- (AD: adult), 17- (MA: middle-aged), and 22- (O: old) month-old Fischer F344 rats. AD rats had the highest acoustic startle reactivity with the Y and MA rats showing smaller and comparable startle levels. The O rats had diminished startle reactivity, with over a 65% reduction in responding. Airpuff startle reactivity was comparable in the Y and AD groups, while the MA and O groups had 40% and 80% reductions in airpuff startle respectively. There was an age-related increase in airpuff startle habituation. Acoustic and cross-modal PPI were reduced significantly in O rats when compared to other age groups. Finally, there were no effects of age on FPS. In summary, these studies suggest that in Fischer F344 rats, there are age-associated differences in startle reactivity, startle habituation, and PPI, but no aging effect on FPS.
authors.affiliation: Department of Psychiatry, University of California San Diego, La Jolla 92093-0804, USA. geoff@mag.ucsd.edu
authors.forename: G B
authors.initials: GB
authors.lastname: Varty
authors.forename: R L
authors.initials: RL
authors.lastname: Hauger
authors.forename: M A
authors.initials: MA
authors.lastname: Geyer
mesh_terms: D000161:Acoustic Stimulation; D000375:Aging / Q000523:psychology*; D000818:Animals; D005239:Fear / Q000502:physiology; D006185:Habituation, Psychophysiologic / Q000502:physiology; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D010812:Physical Stimulation; D051381:Rats; D011916:Rats, Inbred F344; D013216:Reflex, Startle / Q000502:physiology*