Maternal enrichment increases infantile spatial amnesia mediated by postnatal neurogenesis modulation

Area of Science:

• Neuroscience
• Developmental Biology
• Memory Research

Background:

• Infantile amnesia, the inability to form lasting episodic memories, lacks a clear understanding of its origins.
• High rates of hippocampal postnatal neurogenesis have been implicated in the degradation of infant memories.
• Exposure to enriched environments in dams can lead to increased hippocampal neurogenesis in offspring, but its effect on memory persistence is unclear.

Purpose of the Study:

• To investigate how intergenerational increases in hippocampal neurogenesis affect spatial memory retention in mice offspring.
• To determine the causal relationship between postnatal hippocampal neurogenesis and memory failure.
• To explore the impact of inherited high neurogenesis on memory engrams and cognitive performance.

Main Methods:

• Spatial memory retention was evaluated in weaned offspring of enriched female mice.
• The antiproliferative drug Temozolomide (TMZ) was used to assess the causal role of neurogenesis in memory failure.
• Neuronal activity in the hippocampus was quantified by measuring c-Fos expression.

Main Results:

• Offspring of enriched dams exhibited increased spatial memory failure, correlating with higher hippocampal proliferation rates.
• Treatment with TMZ rescued spatial memory retrieval, confirming the role of neurogenesis.
• Differences in c-Fos expression indicated modifications in memory engrams between groups, suggesting altered neural activity patterns.

Conclusions:

• Inherited increases in hippocampal neurogenesis, driven by maternal environmental enrichment, lead to plastic changes.
• These changes exacerbate infantile amnesia in a spatial memory task.
• High neurogenesis rates can modify memory engrams and impact cognitive performance, offering insights into memory persistence.