<p>The present study assessed olfactory and cognitive abilities in two strains of Alzheimer’s disease (AD) model mice and in healthy control mice over a four month time period. To this end an operant conditioning paradigm using an automated olfactometer and a spatial learning test with non-olfactory cues were employed and data on olfactory learning and memory, discrimination, and sensitivity as well as spatial learning and memory were collected. The mice were between 6 to 7 month old at the beginning of the study and 9 to 10 months old at the end of the data collection, that is, in the age range when the animals are supposed to display marked neuroanatomical changes typical of AD. The results demonstrate that there were no systematic differences in olfactory performance and spatial learning and memory abilities of AD model mice and the control mice up to the age they were tested. Further, there was no indication of an age-related decline in performance in any of the mouse strains across the testing period. Several reasons might account for the observed lack of difference in olfactory and cognitive performance between the mouse strains tested here: the AD model mice might not develop amyloid plaques and neurofibrillary tangles at all or they might develop them later than stated by the supplier. Alternatively, the AD model mice may have developed AD-typical neuroanatomical changes but these do not, or not yet, affect their olfactory performance and/or spatial learning and memory capabilities. Ongoing data collection will help to evaluate which of these explanations holds true.</p>

The present study assessed olfactory and cognitive abilities in two strains of Alzheimer’s disease (AD) model mice and in healthy control mice over a four month time period. To this end an operant conditioning paradigm using an automated olfactometer and a spatial learning test with non-olfactory cues were employed and data on olfactory learning and memory, discrimination, and sensitivity as well as spatial learning and memory were collected. The mice were between 6 to 7 month old at the beginning of the study and 9 to 10 months old at the end of the data collection, that is, in the age range when the animals are supposed to display marked neuroanatomical changes typical of AD. The results demonstrate that there were no systematic differences in olfactory performance and spatial learning and memory abilities of AD model mice and the control mice up to the age they were tested. Further, there was no indication of an age-related decline in performance in any of the mouse strains across the testing period. Several reasons might account for the observed lack of difference in olfactory and cognitive performance between the mouse strains tested here: the AD model mice might not develop amyloid plaques and neurofibrillary tangles at all or they might develop them later than stated by the supplier. Alternatively, the AD model mice may have developed AD-typical neuroanatomical changes but these do not, or not yet, affect their olfactory performance and/or spatial learning and memory capabilities. Ongoing data collection will help to evaluate which of these explanations holds true.