A New Treatment Target for Alzheimer's Disease

“Who am I?” is one of the greatest mysteries of life. It digs deep into our very existence, challenging us to question why we think, feel, and experience the world the way we do. For centuries, philosophers, scientists, and thinkers have searched for what sets us apart from other species. Perhaps the answer may lie within a small, often overlooked region of the brain called the precuneus.

Tucked at the back of the parietal lobe, the precuneus may be the window to your inner world. How you think about yourself, reflect on your past, and imagine your future seems to be orchestrated by this region that only emerged in modern humans about 150,000 years ago.

The precuneus stitches together key parts of our identity and consciousness, with new research suggesting its dysregulation may be one of the earliest targets in Alzheimer’s disease. In fact, a recent clinical trial in Italy found that stimulating this region may slow the progression of the disease. Their findings offer a glimpse at how the brain shapes our understanding of who we are.

How We Evolved to Think

The way that we think about ourselves is the result of millions of years of evolution. Unlike most animals (as far as we know), humans have the unique ability not only to experience life, but also to reflect, learn, and predict the future.

When making a major life decision like choosing to go back to school, you are able to weigh the pros and cons and think about how this decision aligns with your personal goals and values. You may try to visualize yourself at that school, how it would feel going to classes and studying. Beyond just making a choice, you are able to recognize your motivations, desires, and the potential consequences of your actions.

This would not have been possible 150,000 years ago, before the rapid brain expansion that marked the late-stage evolution of modern humans. Early homo-sapiens had basic thinking skills that helped them respond to environmental threats and forage for food. These early humans likely were not spending time self-reflecting; they were focused on surviving.

Fossil evidence shows us that as their brains expanded and the precuneus emerged, with it came a whole new way of thinking. They began to use art and language to not only communicate with others but also represent themselves. This evolution of self-awareness gave modern humans the edge they needed to thrive and adapt.

Although many animals show signs of intelligence, like using tools, solving problems, and forming social bonds, very few demonstrate true self-awareness. Only primates, dolphins, elephants, and some birds have shown glimpses of it when they seemingly recognize themselves in a mirror. While some primates and other mammals have brain areas resembling a precuneus, it is much smaller and less developed than in humans.

Loss of Self in Alzheimer’s Disease

We are only just beginning to understand how the precuneus shapes our sense of self. It is becoming clearer that it is deeply tied to memory. More than just remembering facts, self-awareness relies on being able to recall experiences in a way that connects with our identity.

In Alzheimer’s disease, often the first type of memory to be affected is episodic memory. Those are the memories that help you recall specific moments in your life. Your most recent birthday, the last conversation you had with a friend, and your wedding day are all experiences that are tied to emotions, places, and people.

When memory declines, so does the ability to reflect on the past and imagine the future. Over time, reduced self-awareness can make it harder for someone to recognize who they are.

Recent studies suggest that this may be linked to early changes in the precuneus. Brain imaging has shown that the precuneus is one of the first areas to start shrinking in Alzheimer’s disease. Some have suggested that decreased activity in this region may predict disease onset, perhaps even before symptoms become obvious.

A New Treatment Target for Alzheimer’s Disease: The Precuneus

A clinical trial in Italy found that the precuneus could be an effective treatment target for Alzheimer’s. The team ran a year-long study where they applied a non-invasive technique called receptive transcranial magnetic stimulation (rTMS). Using magnetic pulses, this treatment sends gentle, controlled “shocks” through the skull to stimulate a specific area of the brain.

Nearly fifty people with mild-to-moderate Alzheimer’s participated in this study. For the first two weeks, they received daily brain stimulation. This was later reduced to once a week for the remainder of the year. Half the participants were randomly selected to act as controls. They followed the same schedule, but did not receive magnetic stimulation.

A year later, those who received brain stimulation showed a slower decline in their thinking and memory, compared to the control group. These individuals were also better at handling everyday tasks and displayed fewer behavioral changes. The team concluded that direct stimulation of the precuneus may be a safe and effective treatment to help preserve brain function in people with early-stage Alzheimer’s.

What is not yet clear is why this treatment works. One theory is that brain stimulation encourages neuroplasticity, meaning neurons make more connections with each other. Enhancing connections in the precuneus may help the brain reorganize and strengthen neural networks associated with learning and memory.

Animal studies have also suggested that magnetic stimulation may help clear toxic amyloid plaques and tau proteins, the hallmarks of Alzheimer’s disease. Additional studies are needed to understand how long the benefits last and whether this approach could halt the disease completely.

Conclusion

If the precuneus is truly the core of our consciousness, how do we protect it?

The connection between our body, mind, and spirit may be more fragile than we realize. As research races to understand the inner workings of the precuneus, we must do everything that we can to support overall brain health.

Brain stimulation shows promise for those already experiencing cognitive changes. However, for most of us, it will take a mix of healthy eating habits, exercise, and mental wellness to keep our sense of self intact.