A new study suggests that multiple sclerosis lesions linked to memory problems intersect with a memory circuit centered on the hippocampus. By applying a circuit-based approach, researchers showed that lesions associated with MS memory dysfunction connect to a memory circuit.

Between 30 to 50 percent of people living with MS will experience memory problems, but the cause is uncertain. Brain lesions are the hallmark imaging sign used to diagnose MS and are often associated with memory dysfunction. However, increased MS brain lesions are not specific to memory problems and are also linked to fatigue, walking difficulties, and other common MS symptoms. Previous studies that attempted to align the anatomy of lesions linked to memory problems in MS led to conflicting results.

Researchers from Brigham and Women’s Hospital conducted a study to figure out which MS lesion locations are linked to memory issues. The team analyzed imaging and cognitive data from 431 people with MS enrolled in the Comprehensive Longitudinal Investigation of MS at Brigham and Women’s Hospital, or CLIMB study. Researchers mapped white matter lesion locations from each person and tested associations between memory dysfunction and a memory circuit previously derived from strokes causing memory problems. 

They found that MS lesions that were linked to memory problems intersected with this memory circuit centered on the hippocampus. The researchers also analyzed the MS lesion locations compared to large functional and structural brain atlases to identify unique MS memory circuits.

Researchers acknowledged that in many neurologic diseases, they know what brain function will be disrupted based on the location of lesions, but in MS, the lesions are widespread making localization challenging.

The findings were published in the Journal of Neurology.