Abnormal intrinsic brain activity of the putamen is correlated with dopamine deficiency in idiopathic rapid eye movement sleep behavior disorder

Abnormal Striatal-Cortical Networks Contribute to the Attention/Executive Function Deficits in Idiopathic REM Sleep Behavior Disorder: A Resting State Functional MRI Study

“…Meanwhile, intrinsic FCs were also decreased between the striatum, which were involved in production and regulation of motor network (Burciu and Vaillancourt, 2018). One previous study reported similar decreased intrinsic FCs between striatum in both iRBD and PD patients (Li et al, 2020). In de novo PD patients, there were similar decreased FCs between the striatum and motor-related frontal lobe (Esposito et al, 2013).…”

“…Previous study reported similar results that ReHo was decreased in putamen in iRBD. Besides, they found a positive correlation between the decreased ReHo and decreased dopamine transporter in the same region ( Li et al, 2020 ). Several studies have shown that iRBD patients exhibited striatum volume changes, abnormal glucose metabolism and nigrostriatal dopaminergic dysfunction ( Ellmore et al, 2010 ; Vendette et al, 2011 ; Dang-Vu et al, 2012 ; Bauckneht et al, 2018 ; Rahayel et al, 2018a ).…”

“…The analyses of regional homogeneity (ReHo) and functional connectivity (FC) are useful methods in identifying brain network activity changes in neurodegenerative diseases ( Pievani et al, 2011 ). One study detected abnormal spontaneous brain activity of the bilateral putamen in iRBD patients ( Li et al, 2020 ). By setting seed in substantia nigra (SN), iRBD showed abnormal FCs in nigrostriatal and nigrocortical networks ( Ellmore et al, 2013 ).…”

Neurochemical Features of Rem Sleep Behaviour Disorder

“…Table 1 summarizes the results of functional neuroimaging studies with Single Photon Emission Computerized Tomography (SPECT) or Positron Emission Tomography (PET) reported to date in patients diagnosed with RBD, including those using different methods and tracers for the presynaptic dopaminergic (DA) terminal and postsynaptic dopamine D 2 receptors (DRD 2 ). The majority of studies analyzing the presynaptic DA terminal have shown a significant decrease in the striatal tracer uptake in many patients diagnosed, at least initially, with iRBD [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ], with some exceptions [ 45 ], being this decrease lower than that found in patients diagnosed with PD [ 27 , 28 , 31 , 43 , 45 ] or LBD [ 43 ] with or without concomitant RBD, although PD patients with versus those without RBD did not show significant differences [ 46 ]. However, patients with and without decreased striatal tracer uptake did not differ in clinical features according to one study [ 32 ], while in others, iRBD patients with mild motor impairment or with higher Unified Parkinson’s Disease Rating Scale (UPDRS) motor score showed decreased striatal tracer uptake when compared with those without mild motor impairment and with controls [ 33 , 34 ].…”

“…A study on structural connectivity showed decreased measures of the global network, average degree, global efficiency, and local efficiency, and increased measures of characteristic path length in iRBD patients compared to controls [ 175 ]. Two studies measuring amplitude of low-frequency fluctuations (ALFF), showed, respectively, increased ALFF values in the right parahippocampal gyrus [ 182 ], and normal values [ 36 ]. A significant reduction in regional homogeneity in the bilateral putamen of iRBD patients compared with controls has also been described [ 36 ].…”