Indirect structural disconnection-symptom mapping of haptic graviceptic neglect after stroke

Graviceptive neglect (GN), characterized by disturbed verticality perception through visual, postural, or haptic modalities following brain lesions, is a common and incapacitating condition that has been recognized for decades. Yet, the neuroanatomical correlates of haptic GN (H-GN) have been minimally explored OBJECTIVES: We aimed to investigate the brain structures associated with H-GN post-stroke and present the first analysis of associated brain tracts disconnections.

Twelve participants with a first unihemispheric supratentorial or cerebellar ischemic stroke were investigated. H-GN was tested in the frontal plane and estimated using 3 indices: orientation (H_o-GN), uncertainty by the mean of absolute values (H_u-ab-GN), and uncertainty by the standard deviation of H_o-GN (H_u-sd-GN). Lesion subtraction analysis and indirect structural disconnection-symptom mapping were performed.

H_o-GN was associated with the putamen, cerebellum, external capsule, internal capsule, corona radiata, thalamic radiation, and superior longitudinal fasciculus. H_u-sd-GN was associated with the cerebellum. The tracts associated with both H_o-GN and H_u-ab-GN included the corticospinal, extreme capsule, frontopontine, and parietopontine tracts.

All the regions identified are consistent with H-GN-related neural functions, and previous evidence supports this association. By employing innovative methodology, this preliminary study expands knowledge in this field and strengthens the foundation for future replication with larger sample sizes.