Thalamic nuclei volume changes associated with cognitive and motor manifestations of Parkinson's disease.

Motor and cognitive symptoms are key features of Parkinson's disease (PD), which typically appear over time as the disease progresses. The thalamus, a central hub within basal ganglia-thalamocortical circuits, plays a crucial role in motor, sensory, and cognitive functions. This study examined thalamic nuclei volume and lateralization in individuals with PD and healthy controls, and explored their associations with cognitive and motor measures using partial least squares analysis. We found that cognitive alterations were linked to volume changes in specific nuclei of the anterior, ventral, medial, and posterior thalamic nuclear groups. Notably, the anteroventral and ventral posterolateral nuclei showed strong associations with the Montreal Cognitive Assessment used to assess mild cognitive impairment. Motor impairment was associated with volume lateralization asymmetries in the centromedian, mediodorsal medial, pulvinar anterior, and pulvinar medial nuclei. These findings underscore the multifaceted role of the thalamus in the motor and cognitive manifestations of this neurodegenerative disorder.