Michel T.M.,RWTH Aachen |
Michel T.M.,University of Würzburg |
Michel T.M.,King's College London |
Gsell W.,University of Würzburg |
And 13 more authors.
World Journal of Biological Psychiatry | Year: 2010
Objectives. Oxidative stress (OS), is defined as an imbalance of pro-and antioxidants, leading to increased production of free radicals, which can lead to cell damage and death, has been postulated as important factors in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease (AD). Most research has concentrated on the antioxidant system, for the first time, this proof of concept study examines the prooxidant system by investigating kinetic parameters of the free radical producing enzyme xanthine oxidase directly in post mortem brain tissue. Methods. We determined the MichaelisMenten constant (KM) and the maximal velocity (VMax) of xanthine oxidase (XO) in the cortico-limbic system of patients with AD using activity assays. Results. We found the MichaelisMenton constant of XO significantly decreased in hippocampus of patients with AD compared to controls. None of the other brain regions showed any significant alterations of these parameters. Conclusions. These results add further evidence to the amount of research indicating that OS plays an important role in AD. Moreover, these results should encourage more research in this field and it maybe speculated that this might open new avenues for treatment and prevention in AD. © 2010 Informa UK Ltd.
Cieslik E.C.,Jülich Research Center |
Zilles K.,Jülich Research Center |
Zilles K.,Julich Aachen Research Alliance Translational Brain Medicine |
Zilles K.,Heinrich Heine University Düsseldorf |
And 5 more authors.
Journal of Neurophysiology | Year: 2010
Speed and accuracy of motor responses to lateralized stimuli are influenced by the spatial overlap between stimulus location and required response. Responses showing high spatial overlap with peripheral cues benefit from a bottom-up driven enhancement of attention to the respective location, whereas low overlap requires top-down modulated reorienting of resources. Here we investigated the interaction between these two processes using a spatial stimulus-response compatibility task. Subjects had to react to lateralized visual stimuli with a button press using either the ipsilateral (congruent condition) or the contralateral (incongruent condition) index finger. Stimulus-driven bottom-up processes were associated with significant contralateral activation in V5, the intraparietal sulcus (IPS) and the premotor cortex (PMC). Incongruent versus congruent responses evoked significant activation in bilateral IPS and PMC, highly overlapping with the activations found for stimulus-driven bottom-up processes, as well as additional activation in bilateral anterior insula and right dorsolateral prefrontal cortex (DLPFC) and temporoparietal junction (TPJ). Moreover, a region anterior to the bottom-up driven activation in the IPS was associated with top-down modulated directionality-specific reorienting of motor attention during incongruent motor responses. Based on these results, we propose that stimulus-driven activation of contralateral IPS and PMC represent key neuronal substrates for the behavioral advantage observed when reacting toward a congruently lateralized stimulus. Additional activation in bilateral insula and right DLPFC and TPJ during incongruent responses should reflect top-down control mechanisms mediating contextual (i.e., task) demands. Furthermore, this study provides evidence for both overlapping and disparate substrates of bottom-up and top-down modulated attentional processes in the IPS. Copyright © 2010 The American Physiological Society.
Jacobi H.,University of Bonn |
Reetz K.,RWTH Aachen |
Reetz K.,Jülich Research Center |
Reetz K.,Julich Aachen Research Alliance Translational Brain Medicine |
And 34 more authors.
The Lancet Neurology | Year: 2013
Background: Spinocerebellar ataxias (SCAs) are autosomal, dominantly inherited, fully penetrant neurodegenerative diseases. Our aim was to study the preclinical stage of the most common SCAs: SCA1, SCA2, SCA3, and SCA6. Methods: Between Sept 13, 2008, and Dec 1, 2011, offspring or siblings of patients with SCA1, SCA2, SCA3, or SCA6 were enrolled into a prospective, longitudinal observational study at 14 European centres. To be eligible for inclusion in our study, individuals had to have no ataxia and be aged 18-50 years if directly related to individuals with SCA1, SCA2, or SCA3, or 35-70 years if directly related to individuals with SCA6. We did anonymous genetic testing to identify mutation carriers. We assessed participants with clinical scales, questionnaires, and performance-based coordination tests. In eight of the 14 centres, participants underwent MRI. We analysed relations between outcome variables and time from onset (defined as the difference between present age and estimated age at ataxia onset). This study is registered with ClinicalTrials.gov, number NCT01037777. Findings: 276 participants met inclusion criteria and agreed to participate, of whom 12 (4%) were excluded from final analysis because DNA samples were missing or genotyping failed. Estimated time from onset was -9 years (IQR -13 to -6) in 50 carriers of the SCA1 mutation, -12 years (-15 to -9) in 31 SCA2 mutation carriers, -8 years (-11 to -6) in 26 SCA3 mutation carriers, and -18 years (-22 to -16) in 16 SCA6 mutation carriers. Compared with non-carriers of each mutation, SCA1 mutation carriers had higher median scores on the scale for the assessment and rating of ataxia (SARA; 0·5 [IQR 0-1·0] vs 0 [0-0]; p = 0·0052), as did SCA2 mutation carriers (0·5 [0-2·0] vs 0 [0-0·5]; p = 0·0037). SCA2 mutation carriers had lower SCA functional index scores than did non-carriers (-0·43 [-0·91 to -0·07] vs 0·09 [-0·30 to 0·56]; p = 0·0007). SCA2 mutation carriers had worse composite cerebellar functional scores than did their non-carrier counterparts (0·915 [0·861-0·959] vs 0·849 [0·764-0·886]; p = 0·0039). All other differences between carriers and non-carriers were non-significant. In SCA1 and SCA2 mutation carriers, SARA scores were increased in participants who were closer to the estimated age at onset (SCA1: r = 0·36, p = 0·0112; SCA2: r = 0·50, p = 0·0038). 83 individuals (30%) underwent MRI. Voxel-based morphometry showed grey-matter loss in the brainstem and cerebellum in SCA1 and SCA2 mutation carriers, and normalised brainstem volume was lower in SCA2 mutation carriers (median 0·015, range 0·012-0·016) than in non-carriers (0·019, 0·017-0·021; p = 0·0107). Interpretation: Preclinical SCA1 and SCA2 mutation carriers seem to have mild coordination deficits and abnormalities in the brain that are more common in carriers who are closer to the estimated onset of ataxia. Individuals in this early disease stage could be targeted in future preventive trials. Funding: ERA-Net E-Rare and Polish Ministry of Science and Higher Education. © 2013 Elsevier Ltd.
Pohl A.,RWTH Aachen |
Pohl A.,Julich Aachen Research Alliance Translational Brain Medicine |
Anders S.,University of Lübeck |
Schulte-Ruther M.,Julich Aachen Research Alliance Translational Brain Medicine |
And 6 more authors.
PLoS ONE | Year: 2013
Imitation of facial expressions engages the putative human mirror neuron system as well as the insula and the amygdala as part of the limbic system. The specific function of the latter two regions during emotional actions is still under debate. The current study investigated brain responses during imitation of positive in comparison to non-emotional facial expressions. Differences in brain activation of the amygdala and insula were additionally examined during observation and execution of facial expressions. Participants imitated, executed and observed happy and non-emotional facial expressions, as well as neutral faces. During imitation, higher right hemispheric activation emerged in the happy compared to the non-emotional condition in the right anterior insula and the right amygdala, in addition to the pre-supplementary motor area, middle temporal gyrus and the inferior frontal gyrus. Region-of-interest analyses revealed that the right insula was more strongly recruited by (i) imitation and execution than by observation of facial expressions, that (ii) the insula was significantly stronger activated by happy than by non-emotional facial expressions during observation and imitation and that (iii) the activation differences in the right amygdala between happy and non-emotional facial expressions were increased during imitation and execution, in comparison to sole observation. We suggest that the insula and the amygdala contribute specifically to the happy emotional connotation of the facial expressions depending on the task. The pattern of the insula activity might reflect increased bodily awareness during active execution compared to passive observation and during visual processing of the happy compared to non-emotional facial expressions. The activation specific for the happy facial expression of the amygdala during motor tasks, but not in the observation condition, might reflect increased autonomic activity or feedback from facial muscles to the amygdala. © 2013 Pohl et al.
Junger J.,RWTH Aachen |
Junger J.,Julich Aachen Research Alliance Translational Brain Medicine |
Habel U.,RWTH Aachen |
Habel U.,Julich Aachen Research Alliance Translational Brain Medicine |
And 11 more authors.
PLoS ONE | Year: 2014
Gender dysphoria (also known as "transsexualism") is characterized as a discrepancy between anatomical sex and gender identity. Research points towards neurobiological influences. Due to the sexually dimorphic characteristics of the human voice, voice gender perception provides a biologically relevant function, e.g. in the context of mating selection. There is evidence for a better recognition of voices of the opposite sex and a differentiation of the sexes in its underlying functional cerebral correlates, namely the prefrontal and middle temporal areas. This fMRI study investigated the neural correlates of voice gender perception in 32 male-to-female gender dysphoric individuals (MtFs) compared to 20 non-gender dysphoric men and 19 non-gender dysphoric women. Participants indicated the sex of 240 voice stimuli modified in semitone steps in the direction to the other gender. Compared to men and women, MtFs showed differences in a neural network including the medial prefrontal gyrus, the insula, and the precuneus when responding to male vs. female voices. With increased voice morphing men recruited more prefrontal areas compared to women and MtFs, while MtFs revealed a pattern more similar to women. On a behavioral and neuronal level, our results support the feeling of MtFs reporting they cannot identify with their assigned sex. © 2014 Junger et al.