title: Interaction between age and perceptual similarity in olfactory discrimination learning in F344 rats: relationships with spatial learning.
abstract: Emerging evidence suggests that aging is associated with a reduced ability to distinguish perceptually similar stimuli in one's environment. As the ability to accurately perceive and encode sensory information is foundational for explicit memory, understanding the neurobiological underpinnings of discrimination impairments that emerge with advancing age could help elucidate the mechanisms of mnemonic decline. To this end, there is a need for preclinical approaches that robustly and reliably model age-associated perceptual discrimination deficits. Taking advantage of rodents' exceptional olfactory abilities, the present study applied rigorous psychophysical techniques to the evaluation of discrimination learning in young and aged F344 rats. Aging did not influence odor detection thresholds or the ability to discriminate between perceptually distinct odorants. In contrast, aged rats were disproportionately impaired relative to young on problems that required discriminations between perceptually similar olfactory stimuli. Importantly, these disproportionate impairments in discrimination learning did not simply reflect a global learning impairment in aged rats, as they performed other types of difficult discriminations on par with young rats. Among aged rats, discrimination deficits were strongly associated with spatial learning deficits. These findings reveal a new, sensitive behavioral approach for elucidating the neural mechanisms of cognitive decline associated with normal aging.
authors.affiliation: Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Florida, Gainesville, FL, USA.
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Yoder
authors.affiliation: Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA.
authors.forename: Leslie S
authors.initials: LS
authors.lastname: Gaynor
authors.affiliation: Department of Neuroscience, University of Florida, Gainesville, FL, USA.
authors.forename: Sara N
authors.initials: SN
authors.lastname: Burke
authors.affiliation: Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Florida, Gainesville, FL, USA; Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA.
authors.forename: Barry
authors.initials: B
authors.lastname: Setlow
authors.affiliation: Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Florida, Gainesville, FL, USA; Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Smith
authors.affiliation: Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA; Center for Smell and Taste, University of Florida, Gainesville, FL, USA. Electronic address: bizonj@ufl.edu.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Bizon
mesh_terms: D000375:Aging / Q000502:physiology* / Q000523:psychology*; D000818:Animals; D004193:Discrimination Learning / Q000502:physiology*; D018782:Maze Learning / Q000502:physiology; D023421:Models, Animal; D055696:Olfactory Perception / Q000502:physiology*; D011916:Rats, Inbred F344; D012903:Smell / Q000502:physiology*; D065853:Spatial Learning / Q000502:physiology*
keywords: Aging; Odor; Olfaction; Olfactory discrimination; Rat; Spatial learning; Water maze