Summary:
A large neuroimaging study led by researchers at Lund University shows that functional brain connectivity changes in fundamentally different ways during normal aging compared with Alzheimer’s disease. Analyzing resting-state fMRI data from more than 1,000 people, the team found disease-specific patterns of network reorganization that appear long before visible brain atrophy and are closely linked to cognitive performance.
Key Facts:
- Distinct reorganization pathways: Alzheimer’s-related changes follow a unique axis of brain rewiring that is biologically separate from the reorganization seen in normal chronological aging.
- Early, pre-symptomatic shifts: Alzheimer’s-specific connectivity alterations were detectable in cognitively unimpaired individuals with low biomarker levels, well before macroscopic cortical shrinkage.
- Connectivity correlates with cognition: In participants with cognitive impairment, whole-brain functional connectivity patterns aligned more closely with clinical cognitive performance than with regional amyloid‑beta or tau load.
Source: Lund University
Overview: As people age, the brain’s functional organization gradually changes: specialized circuits can lose their segregation, and communication between networks shifts. In neurodegenerative disorders such as Alzheimer’s disease, this breakdown of large-scale communication—often called functional dysconnectivity—intensifies and can precede cell loss and visible tissue atrophy. Because Alzheimer’s pathology typically accumulates during older age, it has been difficult to separate normal aging effects from early disease-related network failure.
A new study published in Nature Neuroscience provides evidence that aging and Alzheimer’s disease alter brain networks along distinct organizational axes. Using resting-state functional MRI from over 1,000 participants spanning young and older cognitively unimpaired adults and individuals across the Alzheimer’s spectrum, the researchers show that the two processes drive coordinated, multi-region shifts in connectivity, rather than isolated regional breakdowns.
“We already knew that blood markers like p‑tau217 can show Alzheimer’s disease before symptoms begin,” said Jonathan Rittmo, the study’s first author and a doctoral researcher at Lund University. “What surprised us is that the specific pattern of altered brain communication was evident even in people with low levels of Alzheimer’s biomarkers who remained cognitively unimpaired.”
The Watercolor Canvas: Coordinated Whole-Brain Shifts
To separate the effects of chronological aging from those driven by Alzheimer’s pathology, the team led by associate senior lecturer Jacob Vogel, Ph.D., examined whole‑cortex connectivity dynamics across two independent cohorts (BioFINDER‑2 and ADNI) that together included more than 1,000 participants. Rather than finding isolated hotspots of dysfunction, they observed coordinated, brain‑wide reorganizations that follow the cortex’s intrinsic functional gradients.
The researchers use a watercolor metaphor to describe the cortex: some functional zones have clear boundaries and remain distinct, while others blend gradually. As connectivity changes, some boundaries become blurrier while others sharpen—yet the direction of those shifts depends on whether the driver is healthy aging or Alzheimer’s disease.
- Alzheimer’s disease: Higher‑order association areas involved in memory and introspection become abnormally similar in their communication profiles, while primary sensory and motor networks become more segregated.
- Normal aging: Connectivity changes follow a different pathway, with regions tied to executive function becoming more alike and peripheral networks showing distinct, separate patterns.
“Our analyses revealed one consistent pattern of reorganization across the adult lifespan and a separate, distinct pattern tied to accumulating Alzheimer’s pathology,” Rittmo explained.
Network Topology Mirrors Cognitive Function
A key clinical insight from the study is that large‑scale functional connectivity patterns tracked cognitive performance more closely than did the regional burden of amyloid‑beta plaques or neurofibrillary tau tangles. While misfolded proteins may initiate cellular toxicity, the disruption of whole‑brain communication channels appears to be more directly related to the cognitive symptoms observed in Alzheimer’s disease.
“Instead of viewing increases or decreases in connectivity as isolated changes in single regions, our results suggest they are components of broader, organized patterns shaped by the brain’s hierarchical architecture,” noted Dr. Vogel.
A New Window for Therapeutic Modulation
The discovery of distinct topological signatures for aging and Alzheimer’s opens potential new avenues for early detection and intervention. Because functional network signaling is biologically malleable, it could be targeted by pharmacological treatments, cognitive training, or non‑invasive neuromodulation such as transcranial electrical or magnetic stimulation. Mapping these early deviations in network dynamics may help guide strategies to preserve cognition or slow disease progression.
The authors emphasize that longitudinal studies are needed to confirm whether individual connectivity patterns can reliably predict who will progress from unimpaired status to dementia. Such follow-up work is already underway to evaluate the prognostic value of these early network changes.
“If these connectivity patterns reflect harmful system‑level stress, then identifying and modulating them could point to new therapeutic directions—potentially even before substantial tissue loss occurs,” Vogel concluded.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full by the editorial team.
- Additional context was added by staff to clarify translational and clinical implications.
About this Alzheimer’s disease Research:
- Media Contact: Anna Elizabeth Hellgren
- Source: Lund University
- Image Credit: Image credited to Neuroscience News
- Original Research (open access): Nature Neuroscience (Sept 22, 2026). Title: “Different functional connectivity gradients reflect aging and Alzheimer’s disease.” Authors: Jonathan Rittmo et al.; Alzheimer’s Disease Neuroimaging Initiative.
- DOI: 10.1038/s41593-026-02402-0
Abstract
Different functional connectivity gradients reflect aging and Alzheimer’s disease
Aging and Alzheimer’s disease (AD) both produce changes in large‑scale brain communication that can be observed with functional connectivity measures. The spatial location, direction and clinical relevance of these changes have been debated, and are infrequently analyzed in the context of whole‑cortex communication dynamics.
In two independent cohorts (BioFINDER‑2, N = 973; Alzheimer’s Disease Neuroimaging Initiative, N = 129), the study shows that connectivity changes associated with aging and AD align with separate, fundamental axes of hierarchical brain communication. Early AD pathology and subsequent cognitive decline are linked to functional changes along the sensory–association axis, while age‑related changes extend along the representation–executive axis throughout adulthood.
Together, these results indicate that Alzheimer’s disease and aging alter major but orthogonal functional pathways in the cortex and support whole‑brain connectivity dynamics as a unifying framework for interpreting functional changes across the adult lifespan.
