The Mammillary Body-Fornix Gate in Long COVID An exploratory structural and diffusion MRI study of tremor-like symptoms, internal vibrations, and neuromuscular fatigue

The study examined brain changes in 88 patients with Long COVID and 34 healthy controls using MRI and diffusion tensor imaging techniques. The research focused on the mammillary bodies, fornix, and connected brainstem-cerebellar system. Results identified three distinct mammillary body volume phenotypes (reduced, enlarged, and normal range), narrowing or loss of a visible internal passage at the hypothalamic interface, and altered diffusion measures in the fornix. Additional findings included lower superior cerebellar peduncle volume and reduced dorsal raphe volume in Long COVID patients. Researchers propose a model in which a vulnerable hypothalamic-limbic interface may contribute to network dysfunction in a subgroup of patients with severe Long COVID. The authors emphasize the need for further prospective studies with standardized methods.