NEURAL IMAGING OF PARKINSON´S DISEASE: A WORLD-WIDE CONSORTIUM APPROACH
Ysbrand D Van Der Werf, Amsterdam
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It has been suggested that slow oscillations in the subthalamic nucleus (STN) reflect top-down inputs from the medial prefrontal cortex, thus implementing behavior control. It is unclear, however, whether the STN oscillations are related to cortical activity in a bottom-up manner. To assess resting-state subcortico-cortical interactions, we recorded simultaneous scalp electroencephalographic activity and local field potentials in the STN (LFP-STN) in 11 patients with Parkinson's disease implanted with deep brain stimulation electrodes in the on-medication state during rest. We assessed the cross-structural phase-amplitude coupling (PAC) between the STN and cortical activity within a wide frequency range of 1 to 100 Hz. The PAC was dominant between the δ/θ STN phase and β/γ cortical amplitude in most investigated scalp regions and between the δ cortical phase and θ/α STN amplitude in the frontal and temporal regions. The cross-frequency linkage between the slow oscillations of the LFP-STN activity and the amplitude of the scalp-recorded cortical activity at rest was demonstrated, and similar involvement of the left and right STNs in the coupling was observed.
Purpose: Despite the best efforts of neurologists, the results of pharmacotherapy in the late stages of Parkinson's disease are often disappointing and accompanied by debilitating side effects. Under these circumstances, deep brain stimulation is a viable treatment option. The aim of the meticulous pre-surgical planning is not only precise electrode implantation, but also the avoidance of intraoperative vascular conflicts potentially causing intracerebral bleeding.
Material and methods: In this report, we present a patient with early-onset Parkinson's disease whose cerebral vascular anatomy precluded standard bilateral subthalamic nucleus electrode implantation. Initially, right subthalamic stimulation alone provided a very mild clinical benefit that was not reflected in the patient's quality of life. In this patient, an unusual configuration of intracerebral electrodes with right subthalamic and left pallidal stimulation electrodes was applied 15 months after the initial subthalamic electrode implantation.
During social interactions, humans tend to imitate one another involuntarily. To investigate the neurocognitive mechanisms driving this tendency, researchers often employ stimulus-response compatibility (SRC) tasks to assess the influence that action observation has on action execution. This is referred to as automatic imitation (AI). The stimuli used frequently in SRC procedures to elicit AI often confound action-related with other nonsocial influences on behaviour; however, in response to the rotated hand-action stimuli employed increasingly, AI partly reflects unspecific up-right/down-left biases in stimulus-response mapping. Despite an emerging awareness of this confounding orthogonal spatial-compatibility effect, psychological and neuroscientific research into social behaviour continues to employ these stimuli to investigate AI. To increase recognition of this methodological issue, the present study measured the systematic influence of orthogonal spatial effects on behavioural and neurophysiological measures of AI acquired with rotated hand-action stimuli in SRC tasks.
Purpose: We aimed to study sex differences in the association of childhood socioeconomic position (SEP) with later-life depressive symptoms, the mediating effect of education and explore regional differences across Europe.
Methods: The study included 58,851 participants (55% women, mean age 65 years) from the multicentre, population-based Survey on Health, Ageing and Retirement in Europe. Interviews were conducted in six waves and included measurements of childhood SEP (household characteristics at the age of 10) and depressive symptoms (EURO-D scale). Linear regression was used to study the association of childhood SEP with depressive symptoms, adjusting for covariates, and structural equation modelling assessed the mediating effect of education.
Results: In the fully adjusted model, higher childhood SEP was associated with lower depressive symptoms with a greater magnitude in women (B = - 0.07; 95% CI - 0.08, - 0.05) than in men (B = - 0.02; 95% CI - 0.03, - 0.00).
Verbal communication relies heavily upon mutual understanding, or common ground. Inferring the intentional states of our interaction partners is crucial in achieving this, and social neuroscience has begun elucidating the intra- and inter-personal neural processes supporting such inferences. Typically, however, neuroscientific paradigms lack the reciprocal to-and-fro characteristic of social communication, offering little insight into the way these processes operate online during real-world interaction. In the present study, we overcame this by developing a "hyperscanning" paradigm in which pairs of interactants could communicate verbally with one another in a joint-action task whilst both undergoing functional magnetic resonance imaging simultaneously. Successful performance on this task required both interlocutors to predict their partner's upcoming utterance in order to converge on the same word as each other over recursive exchanges, based only on one another's prior verbal expressions. By applying various levels of analysis to behavioural and neuroimaging data acquired from 20 dyads, three principle findings emerged: First, interlocutors converged frequently within the same semantic space, suggesting that mutual understanding had been established.
Background: Diffusion kurtosis imaging has been applied to evaluate white matter and basal ganglia microstructure in mixed Parkinson's disease (PD) groups with inconclusive results.
Objectives: To evaluate specific patterns of kurtosis changes in PD and to assess the utility of diffusion imaging in differentiating between healthy subjects and cognitively normal PD, and between PD with and without mild cognitive impairment.
Methods: Diffusion scans were obtained in 92 participants using 3T MRI. Differences in white matter were tested by tract-based spatial statistics. Gray matter was evaluated in basal ganglia, thalamus, hippocampus, and motor and premotor cortices. Brain atrophy was also assessed. Multivariate logistic regression was used to identify a combination of diffusion parameters with the highest discrimination power between groups.
Results: Diffusion kurtosis metrics showed a significant increase in substantia nigra (p = 0.037, Hedges' g = 0.89), premotor (p = 0.009, Hedges' g = 0.85) and motor (p = 0.033, Hedges' g = 0.87) cortices in PD with normal cognition compared to healthy participants.
Differential diagnosis of the most common tremor syndromes - essential tremor (ET) and Parkinson's disease (PD) is burdened with high error rate. However, diagnostic MRI biomarkers applicable in this clinically highly relevant scenario remain an unfulfilled objective. The presented study was designed in search for possible candidate MRI protocols relevant for differential diagnostic process in tremor syndromes.10 non-advanced tremor-dominant PD patients meeting diagnostic criteria for clinically established PD, 12 isolated ET patients and 16 healthy controls were enrolled into this study. The study focused on relaxation MRI protocols - T1, T2, adiabatic T1ρ and adiabatic T2ρ due to their relatively low post-processing requirements enabling implementation into routine clinical practice. Compared to ET, PD patients had significantly longer T2 relaxation times in striata with dominant findings in the putamen contralateral to the clinically more affected body side. This difference was driven by alterations in the PD group as confirmed in the complementary comparison with healthy controls. According to the receiver operating characteristic analysis, this region provided a reasonable sensitivity of 0.91 and specificity of 0.89 in the differential diagnosis of PD and ET.
Background and purpose: Blood pressure (BP) variability has been associated with worse neurological outcomes in acute ischaemic stroke (AIS) patients receiving treatment with intravenous thrombolysis (IVT). However, no study to date has investigated whether pulse pressure (PP) variability may be a superior indicator of the total cardiovascular risk, as measured by clinical outcomes.
Methods: Pulse pressure variability was calculated from 24-h PP measurements following tissue plasminogen activator bolus in AIS patients enrolled in the Combined Lysis of Thrombus using Ultrasound and Systemic Tissue Plasminogen Activator for Emergent Revascularization (CLOTBUST-ER) trial. The outcomes of interest were the pre-specified efficacy and safety end-points of CLOTBUST-ER. All associations were adjusted for potential confounders in multivariable regression models.
Results: Data from 674 participants was analyzed. PP variability was identified as the BP parameter with the most parsimonious fit in multivariable models of all outcomes, and was independently associated (P < 0.001) with lower likelihood of both 24-h neurological improvement and 90-day independent functional outcome.