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Testing for Odor Discrimination and Habituation in Mice
Published on: May 5, 2015
Age effect on olfactory discrimination in a non-human primate, Microcebus murinus
Marine Joly1, Bertrand Deputte, Jean-Michel Verdier
1INSERM U710, Universite Montpellier II, Ecole Pratique des Hautes Etudes, Place E. Bataillon, CC105, 34095 Montpellier Cedex 05, France.
Abstract:
In order to characterize age-related cognitive changes, olfactory discrimination was assessed in Microcebus murinus, a prosimian primate. We compared young (n = 10) and old (n = 8) animals for individual performance on three olfactory tasks. Animals had to perform a detection, a transfer, and a reversal learning task using a go, no go conditioning procedure. No differences were observed between the two groups, indicating that aging is not inevitably associated with a decline in cognitive function. We did, however, observe two aged animals showing altered behavior. One animal displayed impairments in the reversal learning task, and the other showed impairments in both the transfer and reversal tasks. Transfer impairment may be due to a hippocampal alteration, whereas the perseverative tendency noted in the reversal task may be associated with frontal lobe dysfunction. Because some aged M. murinus display lesions that are pathognomonic of Alzheimer's disease, our observations highlight its potential utility as a primate model for studying cognitive deficits in relation to age and associated pathologies.
Insights
Aging does not always impair cognitive function in primates. Some older mouse lemurs (Microcebus murinus) showed normal olfactory discrimination, but a few exhibited deficits potentially linked to Alzheimer's-like brain changes.
Area of Science:
- Primate cognition
- Neuroscience
- Aging research
Background:
- Age-related cognitive decline is a significant concern.
- Understanding cognitive changes in aging primates can inform human aging studies.
- Microcebus murinus (mouse lemurs) offer a valuable model for primate aging research.
Purpose of the Study:
- To investigate age-related changes in olfactory discrimination and cognitive flexibility in mouse lemurs.
- To assess whether aging inevitably leads to cognitive decline in this primate species.
- To explore potential neurological underpinnings of observed cognitive alterations.
Main Methods:
- Olfactory discrimination was assessed in young and old mouse lemurs using detection, transfer, and reversal learning tasks.
- A go, no go conditioning procedure was employed.
- Behavioral performance was compared between age groups.
Main Results:
- No significant differences in olfactory task performance were found between young and old mouse lemurs, suggesting aging does not universally cause cognitive decline.
- Two aged individuals exhibited specific cognitive impairments: one in reversal learning, and another in transfer and reversal learning.
- These impairments may correlate with hippocampal and frontal lobe dysfunction, respectively.
Conclusions:
- Aging is not necessarily associated with a decline in cognitive function in Microcebus murinus.
- The presence of Alzheimer's disease-like lesions in some aged mouse lemurs highlights their potential as a model for studying age-related cognitive deficits and associated pathologies.
- Further research is warranted to explore the link between specific brain alterations and cognitive impairments in aging primates.
