Adult-born neurons maintain hippocampal cholinergic inputs and support working memory during aging

Area of Science:

• Neuroscience
• Cognitive Biology
• Aging Research

Background:

• Adult neurogenesis, the birth of new neurons in the adult brain, declines with age and stress, impacting memory and cognition.
• The precise role of adult neurogenesis in maintaining brain function and connections over a lifetime is not fully understood.
• A systems-level view of how new neurons influence hippocampal function is lacking.

Purpose of the Study:

• To investigate if adult neurogenesis sustains hippocampal connections throughout the lifespan.
• To understand the impact of neurogenesis suppression on brain function and memory.
• To explore the brain's compensatory mechanisms in response to impaired neurogenesis.

Main Methods:

• Long-term suppression of adult neurogenesis in animal models.
• Assessment of hippocampal acetylcholine signaling and working memory.
• Analysis of cholinergic input reorganization in the hippocampus.

Main Results:

• Suppression of neurogenesis led to accelerated decline in hippocampal acetylcholine signaling.
• Progressive working memory deficits emerged with long-term neurogenesis suppression.
• Compensatory reorganization of cholinergic inputs occurred, with potential for functional recovery.

Conclusions:

• Adult neurogenesis is crucial for maintaining the septohippocampal cholinergic circuit and supporting memory across the lifespan.
• This study offers a systems-level explanation for age-related memory decline and cognitive disorders.
• The findings suggest the brain's connectome is adaptable and can be influenced by experience, even in aging.