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Ontogeny of short- and long-term memory capacities for passive avoidance training in undernourished mice
Insights
Early postnatal undernutrition in mice slightly impacts learning but significantly delays the development of both short-term and long-term memory in a passive-avoidance task.
Area of Science:
- Neuroscience
- Developmental Biology
- Animal Behavior
Background:
- Early life nutrition is critical for brain development and cognitive function.
- Undernutrition during sensitive developmental periods can have lasting effects on learning and memory.
- Passive-avoidance tasks are standard models for studying memory acquisition and retention in rodents.
Purpose of the Study:
- To investigate the impact of early postnatal undernutrition on the acquisition and retention of a passive-avoidance response in mice.
- To determine if nutritional status affects the development of short-term and long-term memory in young mice.
- To compare the effects of undernutrition on learning versus memory consolidation.
Main Methods:
- Mice were reared under normal or undernourished conditions (litter sizes of 6 or 16, respectively).
- At 7, 14, or 21 days of age, mice were trained on a passive-avoidance task to avoid shock.
- Memory retention was assessed 1 hour and 24 hours after training.
Main Results:
- Undernutrition caused minimal age-related differences in the acquisition of the passive-avoidance response.
- Retention of the passive-avoidance response was significantly impaired in undernourished mice at both 1-hour and 24-hour intervals.
- These findings suggest undernutrition delays the maturation of memory systems.
Conclusions:
- Early postnatal undernutrition has a more pronounced effect on memory retention than on initial learning in mice.
- The development of both short-term and long-term memory appears to be delayed by early nutritional deficits.
- These results align with previous findings on the effects of undernutrition on memory systems in rodents.
Abstract:
To assess the effects of early postnatal undernutrition upon the developing abilities of infant and juvenile mice to acquire and retain a passive-avoidance response, we reared mice following birth in either "normally nourished" or "undernourished" conditions by maintaining litter sizes of 6 or 16, respectively. At ages ranging from 7 to 21 days, mice from each nutritional condition were trained to withhold stepping off from a small vibrating platform in order to avoid shock. Following training to a common criterion, separate groups of mice were retained to the same criterion either 1 or 24 hr later. From the comparisons with yoked control groups at each age and retention interval, we conclude that although undernutrition results in some age-related differences in the ability to withhold responding, these are quite small during acquisition within each age group. In contrast, the retention data suggest that undernutrition delayed the development of both short- and long-term memory abilities on this task. In general, these results are similar to earlier data involving discriminated shock-escape wherein undernutrition had little apparent effect upon acquisition at the early ages but rather marked effects upon developing memory system.