Aging Brain's Resistance to Dementia: Outsmarting Memory Loss
In the intricate world of the human brain, one structure stands out for its crucial role in memory: the hippocampus. This vital region is primarily involved in the formation, consolidation, and retrieval of long-term memories [1][5]. Acting as an "index," it links different pieces of information to create cohesive memories, transferring information from short-term to long-term memory stores and helping stabilize memory traces over time. It also assists in accessing stored memories when needed [1][5].
The hippocampus is renowned for its efficiency in classifying and encoding memories. It groups similar visual information into categories and uses the precise timing of neuronal activity rather than just firing rates. This temporal coding aids in the storage and retrieval of episodic and visual memories, indicating a sophisticated mechanism by which the hippocampus supports memory function [3].
Contrary to earlier beliefs, recent evidence shows that neurogenesis—the formation of new neurons—continues in the hippocampus well into late adulthood and old age [2][4]. This ongoing neurogenesis supports the hippocampus's adaptability, potentially playing a role in maintaining memory and learning capacity as we age. However, the extent and functional significance of hippocampal neurogenesis in aging humans remain subjects of ongoing research and debate.
Despite the ongoing neurogenesis, changes with age are evident. The number and functional state of synapses change with age, leading to a loss of plasticity in synapses, affecting their ability to be modified [6]. This loss of plasticity could lead to failures in network communication and changes in behaviour.
However, older individuals can recruit additional brain circuits to achieve memory retrieval that is as accurate as that of younger individuals [7]. This adaptability underscores the hippocampus's essential role in memory throughout life, with structural and functional changes possibly influencing age-related memory changes [1][2][4][5].
The hippocampus's role in memory has been extensively studied, with groundbreaking discoveries like John O'Keefe's cognitive maps and Brenda Milner's research in the 1950s [8]. Occasional failure of the hippocampal network function may contribute to changes in memory with age [9]. Older rats, monkeys, and humans show spatial memory impairments [10].
Maintaining brain plasticity is paramount to brain health. Loss of synapses or functional synaptic contacts could lead to failures in network communication and changes in behaviour [6]. Data from humans, monkeys, and rats all support the idea that the hippocampus is fully engaged in spatial navigation [11].
The Precision Aging approach aims to close a gap between optimal cognition and lifespan, increasing the quality of life [12]. Neuroscientist Dr. Carol Barnes, Ph.D., Regents' Professor of psychology at the University of Arizona and the director of the Evelyn F. McKnight Brain Institute, has contributed significantly to our understanding of the aging brain. She developed the Barnes maze, a spatial navigation memory task that is used to measure spatial learning and memory [13].
Dr. Barnes is also known for her research on the aging of the brain in relation to cognitive diseases [14]. Faster decay in synaptic plasticity in older rats correlates with faster forgetting [6]. Despite the changes with age, high levels of brain function is a normative part of aging, and reaching a very old age does not imply having a neurodegenerative disease that results in dementia [15].
In conclusion, the hippocampus is a critical structure for memory, with ongoing neurogenesis supporting its adaptability. However, changes with age, such as the loss of plasticity in synapses, could impact memory function. Understanding these changes is crucial for developing strategies to maintain cognitive health as we age.
- The Precision Aging approach seeks to enhance the quality of life by bridging the gap between optimal cognition and lifespan, focusing on maintaining cognitive healthspan as we age.
- Neuroscientist Dr. Carol Barnes' research on the aging brain has been instrumental in our understanding of the hippocampus's role in spatial memory, as well as the aging process in relation to cognitive diseases.
- Science continues to unravel the intricate mechanisms of the hippocampus, showcasing its importance in both physical health-and-wellness and mental-health, particularly in the preservation of cognitive function during the aging process.
