Digital illustration of a brain split in half, one side showing healthy neural networks and the other showing signs of Alzheimer's.

Unlocking the Alzheimer's Puzzle: How Brain Network Lateralization Holds a Key to Early Detection

Elliot Brynn in Health & Wellness December 2025 • 4 min read.

"New research explores how changes in brain network lateralization, particularly in the default mode network (DMN), could be an early indicator of Alzheimer's disease, offering hope for earlier intervention."

For years, scientists have observed that as we age, the way our brains specialize tasks to one side—a phenomenon called lateralization—tends to shift. Similarly, Alzheimer's disease (AD) brings distinctive changes to brain function and structure. But what if these two processes are connected? Recent research is diving deep into how AD impacts the brain's resting-state lateralization, particularly within a critical network known as the default mode network (DMN).

The DMN is essentially your brain's 'at rest' network—active when you're not focused on specific tasks. It's been found to be vulnerable in aging and AD. Given that language and verbal memory often lean heavily on the left side of the brain, understanding how AD affects this balance could be a game-changer.

This article explores a study from the Alzheimer's Disease Neuroimaging Initiative, which investigates how amyloid pathology—a hallmark of AD—affects the lateralization of the DMN. By comparing groups with and without amyloid buildup, and varying stages of cognitive impairment, the research sheds light on potential new avenues for early diagnosis and intervention.

Decoding the Default Mode Network (DMN) and Alzheimer's Link

Digital illustration of a brain split in half, one side showing healthy neural networks and the other showing signs of Alzheimer's.

The default mode network (DMN) isn't just one homogenous blob of brain activity; it's more like a carefully orchestrated symphony with different sections playing unique roles. The anterior DMN (aDMN) and posterior DMN (pDMN) are two major components, each associated with distinct functions.

Prior research has shown that in individuals with AD, the connectivity within these DMN sections can change. Some studies suggest increased connectivity in the aDMN and decreased connectivity in the pDMN as AD progresses. But here's where it gets interesting: how does the brain's tendency to specialize tasks to one side—lateralization—factor into this?

Brain Regions Involved: The pDMN includes the posterior cingulate cortex, and parts of the temporal lobe, while the aDMN encompasses the medial prefrontal cortex.
Connectivity Changes: AD can lead to enhanced connectivity in the aDMN and reduced connectivity in the pDMN.
Age-Related Shifts: Functional lateralization in components of the DMN can shift as we age.

This study focuses on understanding the interplay between amyloid accumulation, DMN lateralization, and cognitive decline, setting the stage to examine how these factors might provide new biomarkers for AD.

The Future of Alzheimer's Detection: A Call for More Research

This research underscores that exploring functional lateralization, alongside connectivity, is crucial to understanding the intricacies of AD. Further studies that incorporate diverse cognitive assessments, longitudinal designs, and advanced imaging techniques will refine our insights into the relationships between amyloid deposition, DMN lateralization, and cognitive decline. By focusing on these nuanced aspects, we can pave the way for early diagnostic tools and targeted interventions, ultimately improving outcomes for individuals at risk of or affected by Alzheimer's disease.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3233/jad-180541, Alternate LINK

Title: Default Mode Network Lateralization And Memory In Healthy Aging And Alzheimer’S Disease

Subject: Psychiatry and Mental health

Journal: Journal of Alzheimer's Disease

Publisher: IOS Press

Authors: Sarah J. Banks, Xiaowei Zhuang, Ece Bayram, Chris Bird, Dietmar Cordes, Jessica Z.K. Caldwell, Jeffrey L. Cummings

Published: 2018-11-23

Everything You Need To Know

What is the default mode network, and why is it important in the context of Alzheimer's research?

The default mode network, or DMN, is a network of brain regions that are most active when a person is not focused on external stimuli or tasks; it is essentially the brain's "resting state" network. The DMN is significant because it is thought to be crucial for cognitive processes such as self-referential thought, mind-wandering, and remembering the past. Impairment in the DMN has been implicated in several neurological and psychiatric disorders, including Alzheimer's disease. It comprises the anterior DMN (aDMN) and posterior DMN (pDMN), each having distinct functions and connectivity patterns. Understanding its function and changes is vital for deciphering Alzheimer's.

What does brain network lateralization mean, and why is it significant in the study of Alzheimer's disease?

Brain network lateralization refers to the specialization of brain functions to one hemisphere or the other. For example, language and verbal memory functions typically rely on the left side of the brain. The study of lateralization is significant because understanding how Alzheimer's disease affects this specialization could provide insights into the disease's progression and potential biomarkers for early detection. Changes in the lateralization of specific brain networks, like the default mode network, may serve as an early indicator of the disease.

What is amyloid pathology, and why is it important to study in relation to Alzheimer's?

Amyloid pathology refers to the accumulation of amyloid plaques in the brain, which is a hallmark characteristic of Alzheimer's disease. Amyloid plaques are formed from the buildup of amyloid-beta protein fragments and are thought to disrupt normal brain function. Studying amyloid pathology is important in the context of this research because it explores how amyloid accumulation affects the lateralization of the default mode network (DMN). The presence and distribution of amyloid plaques are often used to diagnose and stage Alzheimer's disease.

What are the anterior DMN (aDMN) and posterior DMN (pDMN), and how are they affected by Alzheimer's disease?

The anterior DMN (aDMN) encompasses the medial prefrontal cortex, while the posterior DMN (pDMN) includes the posterior cingulate cortex and parts of the temporal lobe. In individuals with Alzheimer's disease, there are changes in connectivity within these sections; some studies suggest increased connectivity in the aDMN and decreased connectivity in the pDMN as Alzheimer's progresses. Understanding these specific areas helps in dissecting how Alzheimer's impacts different cognitive functions tied to these regions.

Why is exploring the connection between brain network lateralization and Alzheimer's disease important?

This research is important because it suggests that changes in brain network lateralization, particularly in the default mode network (DMN), could serve as an early indicator of Alzheimer's disease. By understanding the relationship between amyloid accumulation, DMN lateralization, and cognitive decline, it paves the way for early diagnostic tools and targeted interventions. This could potentially improve outcomes for individuals at risk of or affected by Alzheimer's disease. Further research incorporating cognitive assessments, longitudinal studies and advanced imaging techniques are required.