Teaching old rats new tricks: age-related impairments in olfactory reversal learning

Schoenbaum, Geoffrey; Nugent, Summer L.; Saddoris, Michael P.; Gallagher, Michela

doi:10.1016/s0197-4580(01)00343-8

Cited by 118 publications

(114 citation statements)

References 46 publications

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“…This type of goal-directed behavior is thought to rely heavily on interconnections between the orbitofrontal cortex and the basolateral amygdala (Saddoris et al, 2005;Schoenbaum, Chiba, & Gallagher, 1998;Schoenbaum et al, 2003bSchoenbaum et al, , 2003c. Additionally, the orbitofrontal cortex has been suggested to be particularly important for odor or visual cue reversal learning (Bohn, et al, 2003;Chudasama & Robbins, 2003;Schoenbaum et al, 2002a). Cellular recordings from orbitofrontal cortex neurons in rats identified as "reversal-learning impaired" revealed reductions in neuronal firing when reward contingencies were reversed in an odor discrimination task, whereas neuronal firing patterns in normal controls and aged "reversallearning unimpaired" rats exhibited a reverse in odor preference (Schoenbaum, et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

“…Other studies have reported that that patients with low odor identification scores who were unaware of their olfactory loss were more likely to develop AD by a two year follow up than other patients (Devanand et al, 2002). A number of researchers have emphasized the importance of the use of animal models to examine age-related changes in cognition and behavior (Gallagher & Rapp, 1997;Schoenbaum, Nugent, Saddoris, & Gallagher, 2002a;Solomon, Beal, & Pendlebury, 1988;Woodruff-Pak & Thompson, 1985). However, few studies have examined age-related odor memory impairments in rodents.…”

Section: Introductionmentioning

confidence: 99%

“…Studies have found that olfactory sensitivity was decreased in aged rats relative to young rats (Apfelbach, Russ, & Slotnick, 1991;Kraemer & Apfelbach, 2004). However, differences in olfactory discrimination have not been detected between young and aged animals (Kraemer & Apfelbach, 2004;Luu, Pirogovsky, & Gilbert, in press;Roman, Alescio-Lautier, & Soumireu-Mourat, 1996;Schoenbaum et al, 2002a). On reversal trials when the reward contingencies were reversed, aged rats showed significant impairments compared to young rats (Roman et al, 1996;Schoenbaum et al, 2002a).…”

Section: Introductionmentioning

confidence: 99%

“…However, differences in olfactory discrimination have not been detected between young and aged animals (Kraemer & Apfelbach, 2004;Luu, Pirogovsky, & Gilbert, in press;Roman, Alescio-Lautier, & Soumireu-Mourat, 1996;Schoenbaum et al, 2002a). On reversal trials when the reward contingencies were reversed, aged rats showed significant impairments compared to young rats (Roman et al, 1996;Schoenbaum et al, 2002a). Therefore, reversal tasks involving olfactory stimuli may be very sensitive to age-related changes in rodents.…”

Section: Introductionmentioning

confidence: 99%

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A comparison of discrimination and reversal learning for olfactory and visual stimuli in aged rats.

Brushfield

Luu²,

Callahan³

et al. 2008

Behavioral Neuroscience

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The present study investigated age-related differences in discrimination and reversal learning for olfactory and visual stimuli in 6 mo and 24 mo old rats. Rats were trained to discriminate between two pseudo-randomly selected odors or objects. Once each animal reached a criterion on discrimination trials, the reward contingencies were reversed. Young and aged rats acquired the olfactory and visual discrimination tasks at similar rates. However, on reversal trials, aged rats required significantly more trials to reach the learning criterion on both the olfactory and visual reversal tasks than young rats. The deficit in reversal learning was comparable for odors and objects. Furthermore, the results showed that rats acquired the olfactory task more readily than the visual task. The present study represents the first examination of age-related differences in reversal learning using the same paradigm for odors and objects to facilitate cross-modal comparisons. The results may have important implications for the selection of memory paradigms for future research studies on aging.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A comparison of discrimination and reversal learning for olfactory and visual stimuli in aged rats.

Brushfield

Luu²,

Callahan³

et al. 2008

Behavioral Neuroscience

View full text Add to dashboard Cite

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“…Olfactory deficits reported in aging rodents include alterations of acuity, discrimination, and memory, although changes are variable depending on the paradigm (3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Olfactory information processing involves successively the OE, OB, and piriform cortex.…”

Section: Are Morphological Changes In the Ob Related To Alterations Inmentioning

confidence: 99%

Age-induced disruption of selective olfactory bulb synaptic circuits

Richard

Taylor²,

Greer³

2010

Proc. Natl. Acad. Sci. U.S.A.

121

125

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Little is known about how normal aging affects the brain. Recent evidence suggests that neuronal loss is not ubiquitous in aging neocortex. Instead, subtle and still controversial, region-and layerspecific alterations of neuron morphology and synapses are reported during aging, leading to the notion that discrete changes in neural circuitry may underlie age-related cognitive deficits. Although deficits in sensory function suggest that primary sensory cortices are affected by aging, our understanding of the age-related cellular and molecular changes is sparse. To assess the effect of aging on the organization of olfactory bulb (OB) circuitry, we carried out quantitative morphometric analyses in the mouse OB at 2, 6, 12, 18, and 24 mo. Our data establish that the volumes of the major OB layers do not change during aging. Parallel to this, we are unique in demonstrating that the stereotypic glomerular convergence of M72-GFP OSN axons in the OB is preserved during aging. We then provide unique evidence of the stability of projection neurons and interneurons subpopulations in the aging mouse OB, arguing against the notion of an age-dependent widespread loss of neurons. Finally, we show ultrastructurally a significant layer-specific loss of synapses; synaptic density is reduced in the glomerular layer but not the external plexiform layer, leading to an imbalance in OB circuitry. These results suggest that reduction of afferent synaptic input and local modulatory circuit synapses in OB glomeruli may contribute to specific age-related alterations of the olfactory function.aging | axodendritic synapses | dendrodendritic synapses | mitral cells A ge-related neurodegenerative diseases, such as Parkinson and Alzheimer's, involve localized or widespread neuronal loss, but little is known about the changes occurring in the brain during normal aging. A growing consensus argues against widespread neuronal loss and atrophy during aging (1, 2). Rather, subtle region-and layer-specific alterations of neuronal morphology and synaptic connections are reported in the neocortex and hippocampus, where they may contribute to age-related cognitive deficits.The laminar organization of olfactory bulb (OB) neurons and synapses provides a simplified cortical model in which we can probe principles of neuronal and synaptic organization during aging. Sensory functions are affected by aging, including alterations in olfactory acuity, discrimination, and memory (3-12). The OB is the first central relay in the pathway processing odor information: it receives afferent input from olfactory sensory neurons (OSNs) located in the olfactory epithelium (OE) and is responsible for detecting odors in the nasal cavity. OSN axons synapse on mitral/tufted cell dendrites in OB glomerular neuropils. OB local interneurons modulate the activity of mitral/tufted cells, contributing to odor signal integration, before propagation to the piriform cortex. Projections from the OE to the OB are organized in an odor receptor (OR) map; each subpopulation of OSNs expressin...

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Social Recognition Assay in the Rat

Mathiasen¹,

DiCamillo²

2010

CP Neuroscience

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Neuropsychiatric disorders encompass a broad patient population in a variety of disease states across all age groups and are often accompanied by deficits in short-term/working memory. However, most preclinical models that allow for an assessment of cognitive enhancement do not provide robust behavioral readouts with a level of throughput sufficient to support modern drug discovery efforts. The rat social recognition assay presented in this unit is one exception that has been increasingly employed to test new chemical entities for enhancing cognitive activity. The test is simple in design and takes advantage of the spontaneous behavior of rats to investigate conspecifics. The protocol in this unit is designed to evaluate the effects of a test substance on the short-term/working memory of adult male rats employing 30-min or 2-hr pretreatment times.

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Teaching old rats new tricks: age-related impairments in olfactory reversal learning

Cited by 118 publications

References 46 publications

A comparison of discrimination and reversal learning for olfactory and visual stimuli in aged rats.

A comparison of discrimination and reversal learning for olfactory and visual stimuli in aged rats.

Age-induced disruption of selective olfactory bulb synaptic circuits

Social Recognition Assay in the Rat

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