Serial reversal learning in an olfactory discrimination task in 3xTg-AD mice.

Male and female 3xTg-AD mice between 5 and 24 mo of age and their B6129F2/J wild-type controls were tested on a series of 18 olfactory discrimination and reversal tasks in an operant olfactometer. All mice learned the odor discriminations and reversals to a criterion of 85% correct, but the 3xTg-AD mice made fewer errors than the B6129F2/J mice in the odor discriminations and in the first six reversal learning tasks. Many mice showed evidence of near errorless learning, and on the reversal tasks the 3xTg-AD mice showed more instances of near errorless learning than the B6129F2/J mice.

A Signal Detection Analysis of Olfactory Learning in 12-Month-Old 5xFAD Mice.

Although Alzheimer's disease is most often studied in terms of memory impairments, olfactory dysfunction begins in the early stages. We tested olfactory learning, sensitivity, and response bias using signal detection methods in 12-month-old male and female 5xFAD mice and their wildtype controls in the operant olfactometer. Odor detection was not reduced in the 5xFAD mice, but learning was, which was worse in female 5xFAD mice than in males.

Measuring Olfactory Processes in Mus musculus.

This paper briefly reviews the literature that describes olfactory acuity and odour discrimination learning. The results of current studies that examined the role of the neurotransmitters noradrenalin and acetylcholine in odour discrimination learning are discussed as are those that investigated pattern recognition and models of human disease. The methodology associated with such work is also described and its role in creating disparate results assessed.

Sex and Genotype Differences in Odor Detection in the 3×Tg-AD and 5XFAD Mouse Models of Alzheimer's Disease at 6 Months of Age.

Deficits in odor identification and detection are early symptoms of Alzheimer's disease (AD). Two transgenic mouse models of AD, the 5XFAD and the 3×Tg-AD mice and their wildtype controls, were assessed for olfactory detection with decreasing concentrations of ethyl acetate in a go no-go operant olfactometer task at 6 months of age. For both the 5XFAD and their B6SJLF1 wildtype littermates, females made fewer errors in detecting the ethyl acetate than males on all but the lowest odor concentrations.

Olfactory delayed matching to sample performance in mice: sex differences in the 5XFAD mouse model of Alzheimer's disease.

While olfactory delayed matching-to-sample tasks have been used to assess working memory in rats, no such tasks have been tested in mice. Olfactory delayed matching-to-sample learning was assessed in male and female 5XFAD mice, a model of Alzheimer's disease, and their wildtype (B6SJL F1) littermates at 6-7 months of age using an operant olfactometer. All 5XFAD and wildtype mice were able to learn the delayed olfactory matching-to-sample task at 2 and 5s delays.

Accessory olfactory bulb function is modulated by input from the main olfactory epithelium.

Although it is now established that sensory neurons in both the main olfactory epithelium and the vomeronasal organ may be activated by both general and pheromonal odorants, it remains unclear what initiates sampling by the vomeronasal organ. Anterograde transport of wheat germ agglutinin-horseradish peroxidase was used to determine that adequate intranasal syringing with zinc sulfate interrupted all inputs to the main olfactory bulb but left intact those to the accessory olfactory bulb. Adult male treated mice were frankly anosmic when tested with pheromonal and non-pheromonal odors and failed to engage in aggressive behavior.

Cognitive impairments in the STOP null mouse model of schizophrenia.

Cognitive dysfunction is a primary and persisting core deficit of schizophrenia that is marginally improved by antipsychotic treatment. Adult mice that lack the stable tubule-only polypeptide (STOP) have neurochemical and behavioral abnormalities that model some features of schizophrenia. Recognition and long-term memory in the STOP null mouse were tested with the novel object recognition task and an olfactory discrimination task, respectively.

Neural cell adhesion molecule (NCAM) null mice do not show a deficit in odour discrimination learning.

Polysialylated neural cell adhesion molecule (PSA-NCAM) is predominantly expressed during development where it regulates biological functions including axon targeting and neuronal precursor cell migration. Although dramatically down regulated after birth in most regions of the nervous system, PSA-NCAM remains highly expressed into adulthood in areas that have ongoing regeneration and plasticity such as in the olfactory bulb and hippocampus. Consequently, lack of PSA-NCAM in NCAM null mice results in distinct morphological changes to these areas.

Repetitive acute pain in infancy increases anxiety but does not alter spatial learning ability in juvenile mice.

We assessed the long-term behavioural effects of a single acute or repetitive inflammatory pain experienced during infancy. Groups of male and female CD1 mice were subjected to either an acute single pain, i.e.