In Alzheimer's disease (AD), structural and functional changes in the brain may give rise to disruption of specific cognitive functions. The aim of this study is to investigate the functional connectivity alterations in the pulvinar's subdivisions and total pulvinar voxel-based morphometry (VBM) changes in individuals with AD and healthy controls.A seed-based functional connectivity analysis was applied to the anterior, inferior, lateral, and medial pulvinar in each hemisphere. Furthermore, VBM analysis was carried out to compare gray matter (GM) volume differences in the pulvinar and thalamus between the two groups. Connectivity analysis revealed that the pulvinar subdivisions had decreased connectivity in individuals with AD. In addition, the pulvinar and thalamus in each hemisphere were significantly smaller in the AD group. The pulvinar may have a role in AD-related cognitive impairments and the intrinsic connectivity network changes and GM loss in pulvinar subdivisions suggest the cognitive deterioration occurring in those with AD.

The claustrum is a sheet‐like of telencephalic gray matter structure whose function is poorly understood. The claustrum is considered a multimodal computing network due to its reciprocal connections with almost all cortical areas as well as subcortical structures. Although the claustrum has been involved in several neurodegenerative diseases, specific changes in connections of the claustrum remain unclear in Alzheimer's disease (AD), and Parkinson's disease (PD). Resting‐state fMRI and T1‐weighted structural 3D images from healthy elderly ( n = 15), AD ( n = 16), and PD ( n = 12) subjects were analyzed. Seed‐based FC analysis was performed using CONN FC toolbox and T1‐weighted images were analyzed with the Computational Anatomy Toolbox for voxel‐based morphometry analysis. While we observed a decreased FC between the left claustrum and sensorimotor cortex, auditory association cortex, and cortical regions associated with social cognition in PD compared with the healthy control group (HC), no significant difference was found in alterations in the FC of both claustrum comparing the HC and AD groups. In the AD group, high FC of claustrum with regions of sensorimotor cortex and cortical regions related to cognitive control, including cingulate gyrus, supramarginal gyrus, and insular cortex were demonstrated. In addition, the structural results show significantly decreased volume in bilateral claustrum in AD and PD compared with HC. There were no significant differences in the claustrum volumes between PD and AD groups so the FC may offer more precise findings in distinguishing changes for claustrum in AD and PD.

The pulvinar is largest thalamic nucleus and has been subdivided into anterior pulvinar (PuA), inferior pulvinar (PuI), medial pulvinar (PuM) and, lateral pulvinar (PuL). Although the function of pulvinar is well known, its role in neurodegenerative diseases is still unclear. We aimed to examine the functional connectivity of PuA, PuI, PuM and, PuL in healthy controls (HC) and patients with Parkinson’s disease (PD). Resting-state fMRI and T1 weighted images of 15 healthy control (HC), and 12 PD patients were used in this study. SPM12 and CONN software were used to preprocessing the imaging data using published pipelines. Seed based resting-state fMRI analyses were carried out to compare the functional connectivity changes between groups. Besides, voxel-based morphometry (VBM) analysis was performed to compare gray matter volume differences between two groups. The bilateral PuI, PuL and PuM exhibited a decreased functional connectivity in the PD group compared to the HC group in the bilateral thalamus, posterior cingulate cortex, cerebellum, and brainstem. Moreover, pulvinar nuclei in each hemisphere had significantly smaller volume in the patients with PD compared to HC. This study highlights that the patients with PD have a smaller volume in pulvinar nuclei in each hemisphere compared to HC. The pulvinar showed less connectivity in the PD group compared to the HC, the diminished connectivity may be associated with hallucination, executive function, and working memory dysfunctions in PD.