Data-driven MEG analysis to extract fMRI resting-state networks.

The electrophysiological basis of resting-state networks (RSN) is still under debate. In particular, no principled mechanism has been determined that is capable of explaining all RSN equally well. While magnetoencephalography (MEG) and electroencephalography are the methods of choice to determine the electrophysiological basis of RSN, no standard analysis pipeline of RSN yet exists.

Clustering of Parkinson subtypes reveals strong influence of DRD2 polymorphism and gender.

Most classification approaches for idiopathic Parkinson's disease subtypes primarily focus on motor and non-motor symptoms. Besides these characteristics, other features, including gender or genetic polymorphism of dopamine receptors are potential factors influencing the disease's phenotype. By utilizing a kmeans-clustering algorithm we were able to identify three subgroups mainly characterized by gender, DRD2 Taq1A (rs1800497) polymorphism-associated with changes in dopamine signaling in the brain-and disease progression.

Probabilistic tractography in the ventrolateral thalamic nucleus: cerebellar and pallidal connections.

The ventrolateral thalamic nucleus (VL), as part of the 'motor thalamus', is main relay station of cerebellar and pallidal projections. It comprises anterior (VLa) and posterior (VLpd and VLpv) subnuclei. Though the fibre architecture of cerebellar and pallidal projections to of the VL nucleus has already been focus in a numerous amount of in vitro studies mainly in animals, probabilistic tractography now offers the possibility of an in vivo comparison in healthy humans.

Hypomania and saccadic changes in Parkinson's disease: influence of D2 and D3 dopaminergic signalling.

In order to understand the influence of two dopaminergic signalling pathways, TaqIA rs1800497 (influencing striatal D2 receptor density) and rs6280 (influencing the striatal D3 dopamine-binding affinity), on saccade generation and psychiatric comorbidities in Parkinson's disease, this study aimed to investigate the association of saccadic performance in hypomanic or impulsive behaviour in parkinsonian patients; besides we questioned whether variants of D2 (A1+/A1-) and D3 (B1+/B1-) receptor polymorphism influence saccadic parameters differently, and if clinical parameters or brain connectivity changes modulate this association in the nigro-caudatal and nigro-collicular tract. Initially, patients and controls were compared regarding saccadic performance and differed in the parameter duration in memory-guided saccades (MGS) and visually guided saccades (VGS) trials ( < 0.0001) and in the MGS trial ( < 0.

Quantitative Susceptibility Mapping and Resting State Network Analyses in Parkinsonian Phenotypes-A Systematic Review of the Literature.

An imbalance of iron metabolism with consecutive aggregation of α-synuclein and axonal degeneration of neurons has been postulated as the main pathological feature in the development of Parkinson's disease (PD). Quantitative susceptibility mapping (QSM) is a new imaging technique, which enables to measure structural changes caused by defective iron deposition in parkinsonian brains. Due to its novelty, its potential as a new imaging technique remains elusive for disease-specific characterization of motor and non-motor symptoms (characterizing the individual parkinsonian phenotype).

Axonal degeneration in Parkinson's disease - Basal ganglia circuitry and D2 receptor availability.

Basal ganglia (BG) circuitry plays a crucial role in the control of movement. Degeneration of its pathways and imbalance of dopaminergic signalling goes along with movement disorders such as Parkinson's disease. In this study, we explore the interaction of degeneration in two BG pathways (the nigro-striatal and dentato-pallidal pathway) with D2 receptor signalling to elucidate an association to motor impairment and medication response.

[Development of an instrument to measure stress conditions in patients with intellectual disabilities and psychiatric disorders: SEAGB-questionnaire].

Aim:  Stress conditions in patients with intellectual disabilities and psychiatric disorders are among all factors the most disabling in their quality of life. We aimed to develop a self-rating and third-person rating instrument verifying the effect of psychiatric and psychotherapeutic treatments in these patients.

Methods:  First, we asked 150 caregivers of residential facility for patients with intellectual disabilities and psychiatric disorders to define 20 words, which describe stress conditions most accurately.

Dopamine substitution alters effective connectivity of cortical prefrontal, premotor, and motor regions during complex bimanual finger movements in Parkinson's disease.

Bimanual coordination is impaired in Parkinson's disease (PD), affecting patients' quality of life. Besides dysfunction of the basal ganglia network, alterations of cortical oscillatory coupling, particularly between prefrontal and (pre-)motoric areas, are thought to underlie this impairment. Here, we studied 16 PD patients OFF and ON medication and age-matched healthy controls recording high-resolution electroencephalography (EEG) during performance of spatially coupled and uncoupled bimanual finger movements.

Thalamic interactions of cerebellum and basal ganglia.

Cerebellum and basal ganglia are reciprocally interconnected with the neocortex via oligosynaptic loops. The signal pathways of these loops predominantly converge in motor areas of the frontal cortex and are mainly segregated on subcortical level. Recent evidence, however, indicates subcortical interaction of these systems.

The differentiated networks related to essential tremor onset and its amplitude modulation after alcohol intake.

The dysregulation of endogenous rhythms within brain networks have been implicated in a broad range of motor and non-motor pathologies. Essential tremor (ET), classically the purview of a single aberrant pacemaker, has recently become associated with network-level dysfunction across multiple brain regions. Specifically, it has been suggested that motor cortex constitutes an important node in a tremor-generating network involving the cerebellum.

Structural differences in impaired verbal fluency in essential tremor patients compared to healthy controls.

Objective: We wanted to identify differences in grey and white matter in essential tremor patients compared to controls in the non-motor domain, using the example of impaired verbal fluency.

Background: A disturbance of verbal fluency in essential tremor patients compared to healthy controls is behaviorally well described.

Methods: Voxel-based morphometry and tract-based spatial statistics were used to analyze structural differences in grey and white matter in 19 essential tremor patients compared to 23 age- and gender-matched controls.

Ageing changes effective connectivity of motor networks during bimanual finger coordination.

Bimanual finger coordination declines with age. However, relatively little is known about the neurophysiological alterations in the motor-system causing this decline. In the present study, we used 128-channel electroencephalography (EEG) to evaluate causal interactions of cortical, motor-related brain areas.

Basal ganglia and cerebellar interconnectivity within the human thalamus.

Basal ganglia and the cerebellum are part of a densely interconnected network. While both subcortical structures process information in basically segregated loops that primarily interact in the neocortex, direct subcortical interaction has been recently confirmed by neuroanatomical studies using viral transneuronal tracers in non-human primate brains. The thalamus is thought to be the main relay station of both projection systems.

Classification of symptom-side predominance in idiopathic Parkinson's disease.

Asymmetry of symptom onset in Parkinson's disease (PD) is strongly linked to differential diagnosis, progression of disease, and clinical manifestation, suggesting its importance in terms of specifying a therapeutic strategy for each individual patient. To scrutinize the predictive value of this consequential clinical phenomenon as a neuromarker supporting a personalized therapeutic approach, we modeled symptom-side predominance at disease onset based on brain morphology assessed with magnetic resonance (MR) images by utilizing machine learning classification. The integration of multimodal MR imaging data into a multivariate statistical model led to predict left- and right-sided symptom onset with an above-chance accuracy of 96%.

Motor loop dysfunction causes impaired cognitive sequencing in patients suffering from Parkinson's disease.

Cognitive impairment in Parkinson's disease (PD) is often attributed to dopamine deficiency in the prefrontal-basal ganglia-thalamo-cortical loops. Although recent studies point to a close interplay between motor and cognitive abilities in PD, the so-called "motor loop" connecting supplementary motor area (SMA) and putamen has been considered solely with regard to the patients' motor impairment. Our study challenges this view by testing patients with the serial prediction task (SPT), a cognitive task that requires participants to predict stimulus sequences and particularly engages premotor sites of the motor loop.

Development and psychometric evaluation of a scale to measure impaired self-awareness of hyper- and hypokinetic movements in Parkinson's disease.

Objective: Patients with Parkinson's disease (PD) can show impaired self-awareness of motor deficits (ISAm). We developed a new scale that measures ISAm severity of hyper- and hypokinetic movements in PD during medication on state and defined its psychometric criteria.

Method: Included were 104 right-handed, non-depressed, non-demented patients.

Parkinson's disease patients with subthalamic stimulation and carers judge quality of life differently.

Background: Quality of life (QoL) improves under subthalamic deep brain stimulation (STN-DBS) in Parkinson's disease (PD), whereas social functioning may be disrupted. This disruption could negatively influence the family dynamic, leading to different perceptions of the STN-DBS outcome by patients and caregivers.

Methods: We recruited 34 PD patients for this prospective, controlled trial, 28 of whom were examined preoperatively, three months and one year after STN-DBS surgery.

Cerebellar networks with basal ganglia: feasibility for tracking cerebello-pallidal and subthalamo-cerebellar projections in the human brain.

Neuroanatomical studies using transneuronal virus tracers in macaque monkeys recently demonstrated that substantial interactions exist between basal ganglia and the cerebellum. To what extent these interactions are present in the human brain remains unclear; however, these connections are thought to provide an important framework for understanding cerebellar contributions to the manifestation of basal ganglia disorders, especially with respect to tremor genesis in movement disorders such as Parkinson's disease. Here, we tested the feasibility of assessing these connections in vivo and non-invasively in the human brain with diffusion magnetic resonance imaging and tractography.