Scientists have discovered that the brain's short-range connections, known as superficial white matter, may help protect cognitive abilities even as gray matter shrinks with age. Healthier connections just beneath the brain's surface were linked to better language skills and appeared to reduce the negative effects of gray matter loss. The study, published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, examined brain imaging and cognitive tests from 459 adults aged 60 and older in India. This research is among the first to explore superficial white matter in a community-based population from a low- and middle-income country. Superficial white matter forms a thin layer of nerve fibers directly under the gray matter that covers the brain's outer surface. These short, curved fibers connect nearby regions of the cerebral cortex, allowing them to share information. Gray matter, on the other hand, contains many of the nerve cells responsible for processing information. Together, gray matter and the white matter beneath it form closely linked systems that may both support cognitive health. The researchers used a type of advanced MRI called diffusion MRI to study these local brain connections. This technique tracks how water moves through brain tissue, revealing microscopic details that traditional scans might miss. They focused on two key measurements: neurite density, which reflects the number of small projections that nerve cells use to send and receive signals, and the amount of freely moving water around these structures. Lower neurite density or higher free water levels can indicate damage, such as loss of myelin (the protective covering of nerve fibers), inflammation, or swelling. Participants also completed tests assessing various cognitive functions, including language, memory, and problem-solving. The strongest link between superficial white matter health and cognitive performance was with language skills. Those with healthier superficial white matter tended to perform better on language tests, particularly in brain regions responsible for word recognition, speech fluency, and temporarily holding language in mind. While gray matter atrophy remained the strongest overall predictor of cognitive ability, the study found that its impact varied depending on the condition of nearby superficial white matter. When these local connections were weaker, gray matter loss was more strongly linked to language difficulties and broader cognitive decline. However, when superficial white matter was healthier, the link between gray matter loss and cognitive decline was less pronounced. This suggests that the brain's local wiring could help explain why two people with similar gray matter loss might not experience the same level of cognitive decline. The study used data from the Harmonized Diagnostic Assessment of Dementia for the Longitudinal Aging Study in India, known as LASI-DAD. More than half of the participants had low literacy, and about 60% lived in rural areas. These groups have been underrepresented in brain imaging research, making this study valuable for understanding cognitive aging across diverse social and educational backgrounds. In this study, the link between superficial white matter and language ability was stronger among individuals with limited literacy or no formal education, and those living in rural areas. The researchers note that their findings do not prove that social factors caused changes in brain tissue. Instead, they suggest that brain aging is influenced by a complex mix of lifelong experiences, including education, health, and environmental factors. Because the study only examined participants at one point in time, it cannot determine the order in which brain changes occur. Future long-term studies will be needed to clarify these relationships. Researchers also plan to explore how factors like vascular health, inflammation, and Alzheimer’s-related proteins interact with changes in gray and white matter.