Strain- and age-dependent divergence in mouse appetitive spatial learning and decision strategies

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Cognitive Science

Background:

• Animals use spatial memory for goal-directed navigation, relying on hippocampal circuits.
• Aging and genetic background influence hippocampal function and spatial memory processing.
• Understanding strain and age interactions is crucial for deciphering spatial memory mechanisms.

Purpose of the Study:

• To investigate how mouse strain (CBA/CaOlaHsd vs. C57BL/6) and age (juvenile vs. mature adult) interact to affect spatial appetitive memory.
• To analyze decision-making strategies using reinforcement learning models in a T-maze task.
• To identify strain- and age-dependent differences in learning, performance, and behavioral policies.

Main Methods:

• Daily training of juvenile and mature CBA/CaOlaHsd and C57BL/6 mice in a T-maze task with probabilistic rewards.
• Measurement of correct choices and latencies across training phases.
• Application of reinforcement learning modeling to trial-by-trial data for strategy assessment.

Main Results:

• CBA/CaOlaHsd mice exhibited lower latencies, faster learning, and superior performance during reward probability decreases compared to C57BL/6 mice.
• Aging increased latencies and modulated performance and decision policies in a strain-dependent manner.
• CBA/CaOlaHsd mice showed higher learning rates and better context exploitation; C57BL/6 mice displayed more omission-driven strategy switching.

Conclusions:

• Spatial learning and decision policies in appetitive memory tasks are significantly influenced by both mouse strain and age.
• Distinct behavioral strategies are employed by different mouse strains under uncertainty and aging.
• These findings highlight the complex interplay of genetic and age-related factors in hippocampal-dependent spatial memory.