Age-related changes in learning and memory in the senescence-accelerated mouse (SAM)

Area of Science:

• Neuroscience
• Gerontology
• Animal Models

Background:

• Aging is associated with cognitive decline, impacting learning and memory.
• Senescence-accelerated mice (SAM) provide a model for studying age-related changes.
• Understanding these changes is crucial for developing interventions for age-related cognitive impairment.

Purpose of the Study:

• To investigate age-related learning and memory deficits in senescence-accelerated mice (SAM).
• To compare learning abilities between senescence-prone (SAM-P/8) and senescence-resistant (SAM-R/1) substrains.
• To characterize the progression of cognitive impairment with age in SAM-P/8 mice.

Main Methods:

• Behavioral testing of learning and memory in SAM-P/8 and SAM-R/1 mice at different ages.
• Assessment of spontaneous motor activity (SMA) and circadian rhythms.
• Evaluation of passive avoidance, one-way active avoidance, and water-filled multiple T-maze tasks.
• Measurement of shock sensitivity using the flinch-jump threshold.

Main Results:

• SAM-P/8 mice showed increased diurnal spontaneous motor activity (SMA) compared to SAM-R/1 mice.
• Impaired acquisition of passive avoidance response in SAM-P/8 mice, worsening with age.
• Delayed acquisition of one-way active avoidance in aged SAM-P/8 mice (12 months).
• Prolonged performance time in the T-maze task for SAM-P/8 mice, increasing with age.
• No significant difference in shock sensitivity or T-maze errors between the groups.

Conclusions:

• Senescence-prone SAM-P/8 mice display significant age-related learning and memory impairments.
• These deficits manifest in various behavioral tasks, including passive avoidance and spatial navigation.
• The findings highlight the utility of SAM-P/8 mice as a model for studying accelerated cognitive aging.