The odour span task: a novel paradigm for assessing working memory in mice

Area of Science:

• Neuroscience
• Olfactory System Research
• Cognitive Impairment Models

Background:

• Olfactory dysfunction is an early indicator of Alzheimer's, schizophrenia, and mild cognitive impairment.
• Existing animal models lack sufficient tasks to evaluate olfactory working memory.
• Caspase-3 is prevalent in the olfactory system, suggesting a potential role in olfactory memory.

Purpose of the Study:

• To develop and validate a novel mouse odour span task for assessing olfactory working memory.
• To investigate the impact of caspase-3 overexpression on olfactory working memory in mice.
• To explore the therapeutic potential of nicotine in reversing olfactory working memory deficits.

Main Methods:

• Development of a mouse odour span task to measure the capacity for remembering increasing numbers of odors.
• Utilizing transgenic mice overexpressing human caspase-3 (Tg) and comparing them to wild-type littermates.
• Assessing performance in the odour span task, odor discrimination, and locomotor activity.

Main Results:

• Transgenic mice overexpressing caspase-3 exhibited significant, age-independent deficits in olfactory working memory.
• These mice showed impaired task acquisition, reduced span lengths, lower accuracy, and higher error rates.
• Nicotine administration successfully reversed the observed working memory impairments in Tg mice.

Conclusions:

• The mouse odour span task effectively detects olfactory working memory impairments caused by genetic modification.
• Caspase-3 overexpression selectively impairs olfactory working memory, not odor discrimination or general locomotion.
• The findings support the utility of the odour span task for evaluating animal models of neurological diseases and testing potential therapeutics.