Circadian activity associated with spatial learning and memory in aging rhesus monkeys

Area of Science:

• Neuroscience
• Primate Cognition
• Behavioral Science

Background:

• Spatial learning and memory tests in rodents and nonhuman primates often assess different neural systems due to task design.
• A navigational component is typically absent in primate spatial memory tests, limiting direct comparison with rodent models.

Purpose of the Study:

• To develop and validate a novel navigational spatial learning and memory task for nonhuman primates.
• To assess the performance of elderly female rhesus monkeys on this new task.
• To investigate the association between circadian activity and performance in spatial navigation.

Main Methods:

• Developed a room-based navigational task where rhesus monkeys located baited food ports.
• Assessed performance using trials to criterion and search strategies after initial learning and a location shift.
• Measured circadian activity using accelerometers, analyzing parameters like daily activity and sleep-wake patterns.

Main Results:

• Rhesus monkeys successfully learned the navigational task, as indicated by improved search strategies.
• Significant correlations were observed between task performance (trials to criterion) and circadian activity measures.
• Disruptions in circadian rhythms, including reduced daily activity and altered sleep patterns, were linked to poorer spatial task performance.

Conclusions:

• The developed navigational task is a valuable tool for assessing spatial learning and memory in rhesus monkeys.
• Circadian activity plays a significant role in spatial navigational performance in nonhuman primates.
• This task allows for closer parallels between rodent and primate studies of spatial cognition.