Striatal dopamine transporter degeneration in right-handed REM sleep behavior disorder patients progresses faster in the left hemisphere

Brain network analysis reveals hemispheric aberrant topology in patients with idiopathic REM sleep behavior disorder

Idiopathic REM sleep behavior disorder (iRBD) is recognized as a prodromal stage of neuro-degenerative disease. While brain network analysis is a well-documented approach for characterizing disease-related dysfunctions, the specific patterns in iRBD, particularly those related to hemispheric aberrations remain largely unexplored. To address this gap, this study investigated the topological abnormalities of multi-band EEG networks in patients with iRBD. Specifically, eyes-open resting-state EEG signals were collected from 30 iRBD patients and 30 matched health control (HC) participants. Graph theoretical analysis was then employed to explore network properties at the whole-brain and the hemispheric level. At the whole-brain level, we found aberrant increased local and global efficiency along with a distinct pattern of increased frontal and decreased parietal nodal efficiency in alpha band of iRBD patients. At the hemispheric level, iRBD networks displayed more efficient topological properties in the left hemisphere. Additionally, significant hemispheric asymmetry was observed in alpha-band iRBD network compared to that of HC. In sum, these findings provide novel insights into the disrupted network reorganization in iRBD and suggest aberrant hemispheric asymmetry as a potential neural biomarker for early diagnosis and monitoring of the disease.

Neuroanatomical and clinical correlates of prodromal dementia with Lewy bodies: a systematic literature review of neuroimaging findings

Prodromal Dementia with Lewy bodies (pro-DLB) has been recently defined; however, the neuroanatomical and functional correlates of this stage have not yet been univocally established. This study aimed to systematically review neuroimaging findings focused on pro-DLB. A literature search of works employing MRI, PET, and SPECT was performed. Forty records were included: 15 studies assessed gray matter (GM) and white matter (WM) integrity, and 31 investigated metabolism, perfusion, and resting-state connectivity. Results showed that, in pro-DLB, frontal lobe areas were characterized by decreased function, cortical atrophy, and WM damage. Volumetric reductions were found in the insula, which also showed heightened metabolism. A pattern of hypofunction and structural damage was observed in the lateral and ventral temporal lobe; instead, the parahippocampal cortex and hippocampus exhibited greater function. Hypofunction marked parietal and occipital regions, with additional atrophy in the medial occipital lobe and posterior parietal cortex. Subcortically, atrophy and microstructural damage in the nucleus basalis of Meynert were reported, and dopamine transporter uptake was reduced in the basal ganglia. Overall, structural and functional damage was already present in pro-DLB and was coherent with the possible clinical onset. Frontal and parieto-occipital alterations may be associated with deficits in attention and executive functions and in visuo-perceptual/visuo-spatial abilities, respectively. Degeneration of cholinergic and dopaminergic transmission appeared substantial at this disease stage. This review provided an updated and more precise depiction of the brain alterations that are specific to pro-DLB and valuable to its differentiation from physiological aging and other dementias.

Porous carbon nanosheets derived from two-dimensional Fe-MOF for simultaneous voltammetric sensing of dopamine and uric acid

It is of great significance for electrochemical sensors to simultaneously detect dopamine (DA) and uric acid (UA) related to biological metabolism. In this work, two-dimensional (2D) porous carbon nanosheets (CNS) was prepared as electrocatalysts to improve the sensitivity, the selectivity, and the detection limit of the simultaneous detection. First, 2D amorphous iron-metal organic frameworks (Fe-MOF) was synthesized with Fe3+and terephthalic acid via a facile wet chemistry method at room temperature. And then, CNS was prepared by pyrolysis and pickling of Fe-MOF. CNS had large specific surface area, good electrical conductivity and lots of carbon defects. The response currents of the CNS modified electrode was larger than those of the control electrodes in the simultaneous determination. The simultaneous determination was measured via differential pulse voltammetry to reduce the effect of capacitive currents on quantitative analysis. The CNS modified electrodes showed high sensitivity and low detection limit for the simultaneous detection of DA and UA. The modified electrodes have been successfully used to detect DA and UA in normal human serum.

Amplitude of low-frequency fluctuation-based regional radiomics similarity network: Biomarker for Parkinson's disease

Parkinson's disease (PD) is a highly heterogeneous disorder that is difficult to diagnose. Therefore, reliable biomarkers are needed. We implemented a method constructing a regional radiomics similarity network (R2SN) based on the amplitude of low-frequency fluctuation (ALFF). We classified patients with PD and healthy individuals by using a machine learning approach in accordance with the R2SN connectome. The ALFF-based R2SN exhibited great reproducibility with different brain atlases and datasets. Great classification performances were achieved both in primary (AUC = 0.85 ± 0.02 and accuracy = 0.81 ± 0.03) and independent external validation (AUC = 0.77 and accuracy = 0.70) datasets. The discriminative R2SN edges correlated with the clinical evaluations of patients with PD. The nodes of discriminative R2SN edges were primarily located in the default mode, sensorimotor, executive control, visual and frontoparietal network, cerebellum and striatum. These findings demonstrate that ALFF-based R2SN is a robust potential neuroimaging biomarker for PD and could provide new insights into connectome reorganization in PD.

Gastrointestinal Symptoms and Dopamine Transporter Asymmetry in Early Parkinson's Disease

Background

The neurophysiological correlates of gastrointestinal symptoms (GISs) in Parkinson's disease (PD) are not well understood. It has been proposed that in patients with a gastrointestinal origin of PD dopaminergic neurodegeneration would be more symmetric.

Objectives

The aim is to assess the associations between GISs and asymmetry of nigrostriatal dopaminergic neurodegeneration in PD.

Methods

Ninety PD patients were assessed using motor and GIS scales and ¹²³I‐FP‐CIT SPECT. We calculated the asymmetry index and the predominant side of motor symptoms and dopamine transporter (DAT) imaging defect and assessed their association with GISs.

Results

There were no significant differences in GISs between symmetric and asymmetric dopaminergic defect. Left predominant defect was related to more GIS and higher constipation scores.

Conclusions

GISs were associated with left predominant reduction in putaminal DAT binding but not asymmetry per se. It remains open whether left‐sided DAT deficit is related to more pronounced GI involvement or symptom perception in PD. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson Movement Disorder Society.