Abstract # 1229 Event # 30:

Scheduled for Monday, June 26, 2006 02:00 PM-02:20 PM: Session 4 (Kama B)

Olfactory discrimination and aging in an archaic primate: a behavioral and fMRI approach

M. Joly1,2, B. Deputte3 and J. M. Verdier1
1UMR 710, INSERM/EPHE, Place E. Bataillon, cc 105, Montpellier 34095, France, 2Institute of Zoology, University of Veterinary Medicine, Hannover, Germany, 3Ecole Nationale Vétérinaire d´Alfort, France
     Previous studies have shown that aged Microcebus murinus may present Alzheimer-like lesions in their brains. In humans, this pathology is linked to olfactory impairments. We thus tested the effect of aging on olfactory abilities in mouse lemurs in designing a two-odor discrimination task (learning task), and assessing cognitive flexibility through transfer and reversal tasks. Our results showed that young (n=10) and old (n=8) mouse lemurs were able to succeed in all the three tasks. No significant difference was observed in individual performances between young and aged lemurs. However, two aged individuals displayed performances in transfer and reversal tasks that were outside of the range of performances of the young or the other aged lemurs. Our results confirmed that aging is not always linked with impairments in cognitive abilities, but may be due to associated pathologies. In order to check olfactory information integration of these animals, we developed a functional Magnetic Resonance Imaging (fMRI) approach for the olfactory bulb. We were able to record activation before and during an odor stimulation. We observed that the bulb is specifically activated by odors suggesting an odor-specific representation. Our results are in agreement with similar studies in rodents. To our knowledge, this study is the first combining behavioural and fMRI analyses of olfactory abilities in a non-human primate. It opens the way for studies on cerebral aging and associated pathologies.