Causes and prevention of cognitive decline in later life.

Causes and prevention of cognitive decline in later life.

The Science Behind Cognitive Decline and How to Slow It Down

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As we age, our thinking and memory skills naturally decline, leading to age-related syndromes such as dementia. While the exact cause of cognitive decline is still unknown, recent studies conducted on mice models have shed light on the central mechanisms behind normal aging-related cognitive decline and identified potential ways to slow it down.

Understanding Cognitive Decline

Cognition, which encompasses thinking, learning, memory, awareness, and judgment, undergoes changes as we age. The brain’s nerve cells and synapses gradually alter over time, resulting in a decline in our ability to process information quickly and make decisions. Typically, people start to notice this decline around the age of 50. However, this slight drop in processing speed and working memory is often accompanied by improvements in accumulated knowledge well into old age.

The Central Mechanism of Cognitive Decline

A recent study, published in Science Signaling, investigated the role of CaM kinase II (CaMKII), an enzyme involved in synaptic plasticity and nerve impulse transmission. By altering this brain protein in mice, the researchers were able to mimic the cognitive effects associated with normal aging. The study found that a process called S-nitrosylation, which relies on nitric oxide (NO), modifies CaMKII. Reduced nitrosylation of CaMKII during normal aging impairs memory and learning abilities by reducing synaptic localization and impairing its synaptic functions.

Slowing Cognitive Decline with Lifestyle Factors

It is widely known that a healthy lifestyle can boost brain health and potentially slow cognitive decline. A 2015 study suggested that exercise, intermittent fasting, and critical thinking are essential for optimal brain health throughout life. Another study found that a healthy lifestyle is associated with a slower rate of memory decline in adults with normal cognition. Furthermore, positive experiences such as social interaction, physical exercise, and cognitive training have been shown to be beneficial for cognitive health.

A Mechanism for Cognitive Preservation

To understand how these positive experiences benefit cognitive health, researchers conducted a study published in Aging using mice models. Adult and elderly mice were placed in an enriched environment for 10 weeks, which included larger cages with various toys and stimuli. The control group was kept in standard cages with limited stimuli. Afterward, the mice underwent tests to evaluate their spatial working memory, cognitive flexibility, and spatial reference memory.

The study revealed that mice in the enriched environment had improved performance on all cognitive tasks compared to those in the standard environment, particularly in the older mice. The researchers identified the involvement of an enzyme called MSK1, which is linked to neuronal proliferation, synaptic plasticity, and gene expression. Mice with a mutation in MSK1 did not experience the same cognitive benefits from the enriched environment. This suggests that MSK1 plays a crucial role in the cognitive benefits of environmental enrichment.

Embracing Exercise, Socializing, and Learning

While the studies mentioned above were conducted in mice, research in humans has shown that aging also reduces nitrosylation of CaMKII. This opens up the possibility of developing pharmacological treatments to increase nitrosylation and alleviate cognitive deficits associated with normal aging. Inhibitors of GSNOR, an enzyme that limits nitric oxide bioavailability and is more expressed with aging, are among the potential approaches.

However, waiting for pharmacological treatments may not be necessary. According to Professor Bruno Frenguelli, a neuroscience professor at the University of Warwick, lifestyle enrichment can provide significant cognitive benefits. The brain growth factor BDNF, which activates MSK1, has been implicated in these benefits in both rodents and humans. This finding offers opportunities to explore BDNF and other molecules as potential drug targets.

Professor Frenguelli emphasizes that it’s never too late to benefit from exercise, social interactions, and cognitive stimulation. Recent findings demonstrate that these benefits can occur even in very old mice, equivalent to individuals in their 70s. This implies that engaging in enrichment activities can have positive effects on cognitive health among the elderly.

In conclusion, understanding the mechanisms behind cognitive decline is crucial for developing strategies to slow down this natural process. While more research is needed, these studies emphasize the potential benefits of lifestyle factors such as exercise, social interaction, and cognitive training in preserving cognitive function. By actively embracing these practices, we can promote healthy cognitive aging and potentially delay the onset of age-related cognitive decline.