Chabran E, Noblet V, de Sousa PL, et al. - In order to determine the neural correlates of fluctuations, one of the core clinical features characterizing dementia with Lewy bodies (DLB), researchers examined patients with DLB, patients with Alzheimer disease (AD) and healthy elderly individuals for the structural and functional changes. Further, they assessed their potential correlation with fluctuations. They assessed structural and resting-state functional MRI data from 92 DLB patients, 70 AD patients, and 22 control individuals, who also underwent a thorough clinical examination including the Mayo Clinic Fluctuation Scale. Findings suggest a correlation of functional connectivity changes, not of significant gray matter loss, with the emergence of fluctuations in DLB patients. In the DLB group, fluctuations seemed to be correlated with disturbances of the external functional connectivity of the salience network (responsible for switching between the default mode network and attentional executive networks), which may result in less relevant transitions from one cognitive state to another in response to internal and environmental stimuli. They also observed the relation of higher fluctuation scores with a lower thalamic functional connectivity, inferring a possible value of the thalamus as a key region for the occurrence of this symptom.