Intra‐ and inter‐network functional alterations in <scp>P</scp>arkinson's disease with mild cognitive impairment

<jats:title>Abstract</jats:title><jats:p>Mild cognitive impairment (MCI) is prevalent in 15%–40% of Parkinson's disease (PD) patients at diagnosis. In this investigation, we study brain intra‐ and inter‐network alterations in resting state functional magnetic resonance imaging (rs‐fMRI) in recently diagnosed PD patients and characterise them as either cognitive normal (PD‐NC) or with MCI (PD‐MCI). Patients were divided into two groups, PD‐NC (<jats:italic>N</jats:italic> = 62) and PD‐MCI (<jats:italic>N</jats:italic> = 37) and for comparison, healthy controls (HC, <jats:italic>N</jats:italic> = 30) were also included. Intra‐ and inter‐network connectivity were investigated from participants’ rs‐fMRIs in 26 resting state networks (RSNs). Intra‐network differences were found between both patient groups and HCs for networks associated with motor control (motor cortex), spatial attention and visual perception. When comparing both PD‐NC and PD‐MCI, intra‐network alterations were found in RSNs related to attention, executive function and motor control (cerebellum). The inter‐network analysis revealed a hyper‐synchronisation between the basal ganglia network and the motor cortex in PD‐NC compared with HCs. When both patient groups were compared, intra‐network alterations in RSNs related to attention, motor control, visual perception and executive function were found. We also detected disease‐driven negative synchronisations and synchronisation shifts from positive to negative and vice versa in both patient groups compared with HCs. The hyper‐synchronisation between basal ganglia and motor cortical RSNs in PD and its synchronisation shift from negative to positive compared with HCs, suggest a compensatory response to basal dysfunction and altered basal‐cortical motor control in the resting state brain of PD patients. <jats:italic>Hum Brain Mapp 38:1702–1715, 2017</jats:italic>. © 2016 Wiley Periodicals, Inc.</jats:p>