Alternations of the Pulvinar in Posterior Cortical Atrophy: A Multimodal MRI Study

Abstract

Background: Although the pulvinar is known for its visual function and extensive connections with cortical areas, the volumetric change and functional connectivity of the pulvinar in posterior cortical atrophy (PCA) remain unclear.

Objective: To identify functional and volumetric changes of the pulvinar in PCA patients and the relevant associations with higher visual dysfunction.

Methods: A total of 29 patients with PCA and 30 normal controls were recruited. Each participant underwent a comprehensive neuropsychological assessment and both structural and resting-state functional MRI scanning. Voxel-based morphometry (VBM) and seed-based functional connectivity analyses were conducted to assess pulvinar gray matter volume as well as functional connectivity between the pulvinar and whole brain regions. A partial correlation analysis was performed to analyze neuropsychological tests and pulvinar imaging data.

Results: Cognitive and visual functions including visuospatial processing, visual perception, episodic memory, and naming were impaired among PCA patients. Marked pulvinar atrophy was noted in PCA patients. Furthermore, functional connectivity between the pulvinar and precuneus was significantly decreased in PCA patients as compared to normal controls (FWE corrected; P<0.001). Gray matter volume of the left pulvinar was found to associate with object agnosia (r=0.53, P=0.005) and prosopagnosia (r=0.54, P=0.005) among PCA patients. Gray matter volume of the right pulvinar was found to be associated with the Clinical Dementia Rating scale (r=-0.52, P=0.006) and Activities of Daily Living (r=-0.59, P=0.002) scores. Prosopagnosia correlated positively to the functional connectivity of the left pulvinar and left middle temporal.

Conclusion: Our findings support pulvinar degeneration and its contributions in PCA.

Note:
Funding declaration: This work was supported by grants from the National Natural Science Foundation of China [No. 82271464] and sponsored by Beijing Nova Program.

Conflict of Interests: None.

Ethical Approval: Written informed consent was obtained from either individual participants or family members according to the Declaration of Helsinki. The informed consent form was approved for use by the Ethics Committee on Human Clinical Research of Xuanwu Hospital, Capital Medical University.

Keywords: Alzheimer's disease, posterior cortical atrophy, pulvinar, MRI, functional connectivity, neuropsychological tests