150 Psychologie
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Reducing neuronal size results in less cell membrane and therefore lower input conductance. Smaller neurons are thus more excitable as seen in their voltage responses to current injections in the soma. However, the impact of a neuron’s size and shape on its voltage responses to synaptic activation in dendrites is much less understood. Here we use analytical cable theory to predict voltage responses to distributed synaptic inputs and show that these are entirely independent of dendritic length. For a given synaptic density, a neuron’s response depends only on the average dendritic diameter and its intrinsic conductivity. These results remain true for the entire range of possible dendritic morphologies irrespective of any particular arborisation complexity. Also, spiking models result in morphology invariant numbers of action potentials that encode the percentage of active synapses. Interestingly, in contrast to spike rate, spike times do depend on dendrite morphology. In summary, a neuron’s excitability in response to synaptic inputs is not affected by total dendrite length. It rather provides a homeostatic input-output relation that specialised synapse distributions, local non-linearities in the dendrites and synaptic plasticity can modulate. Our work reveals a new fundamental principle of dendritic constancy that has consequences for the overall computation in neural circuits.
Hintergrund: Depressionen sind häufige, schwere und oft lebensbedrohliche Erkrankungen, bei denen es – trotz sehr guter Behandlungsmethoden – Versorgungslücken gibt. Hierzu tragen Vorbehalte gegen eine leitlinienkonforme pharmako- und/oder psychotherapeutische Behandlung bei. Ziel der Arbeit ist es zu ermitteln, in welchen soziodemographischen Bevölkerungssegmenten diese Vorbehalte besonders ausgeprägt sind.
Methodik: Die Untersuchung basiert auf Online-Befragungen der deutschen Bevölkerung aus den Jahren 2021, 2020 und 2019, darunter 1656 Personen (2021), 1775 Personen (2020) und 1729 Personen (2019) ohne Depressionserfahrungen. Mit einer CHAID-Analyse wurde geprüft, in welchen Bevölkerungssegmenten die Vorbehalte gegen eine leitliniengerechte Behandlung besonders groß sind.
Ergebnisse: Vorbehalte gegen Pharmakotherapie hatten insgesamt 69,8 % der Befragten ohne Depressionserfahrungen. Am größten waren die Vorbehalte unter jüngeren Personen (< 40 Jahre); hier lag der Anteil bei 74,2 %. Vorbehalte gegen Psychotherapie äußerten 31,4 % ohne Depressionserfahrungen; unter Frauen mit geringerer Schulbildung hatten 40,5 % Vorbehalte gegen eine Psychotherapie; unter Männern mit geringerer Schulbildung waren es 39,1 %. Vorbehalte gegen beide Behandlungsformen zeigten 27,7 %. Am größten waren die Vorbehalte unter Männern mit Schulbildung unterhalb der Hochschulreife (34,1 %). Die Ergebnisse sind signifikant (χ2-Test, p < 0,05).
Diskussion: Eine allgemeine Informationsstrategie wäre geeignet, Vorbehalten gegen Pharmakotherapie und Psychotherapie gleichermaßen zu verringern. Für eine spezifische Informationsstrategie müssen die Botschaften hinsichtlich Inhalt und Kommunikationskanälen so gestaltet werden, dass die jüngere Zielgruppe zuverlässig erreicht wird.
Circulating monocytes contribute to inflammatory processes. We here validate abnormal expression of inflammation-related genes in monocytes of a large and well-characterised group of MDD patients, and relate the outcomes to pertinent clinical characteristics. Thirty-two genes of a previously established inflammation-related gene signature were assessed in 197 patients with MDD, and 151 controls collected during the EU-MOODINFLAME project. Monocyte gene- expression data were related to age, sex, BMI, depression severity, childhood adversity (CA) and suicide risk (SR). Three distinct gene profiles were identified within the MDD group (downregulated, mixed upregulated and strongly upregulated genes). Patients in the merged upregulated groups had a significantly higher prevalence of CA and high SR. Using hierarchical clustering of the genes, we found a cluster of mainly cytokine (production)-related genes; patients with SR had a significantly higher expression of this cluster than patients without SR (particularly for IL-6, IL1A and IL1B). Such difference did not emerge for patients with and without CA. A downregulated gene profile was found for patients not exposed to CA and without SR (particularly for glucocorticoid-signalling genes NR3C1a and HSPA1/B). No inflammatory changes were observed for healthy controls exposed to CA. Our data show that inflammatory activation in MDD is not uniform, and that immunologically discernible phenotypes of depression can be linked to CA and high SR. The absence of monocyte inflammatory activation in healthy controls exposed to CA suggests an inflammatory involvement in MDD-prone individuals exposed to early stressors, but not healthy controls.
Purpose: In this study, we examined distress levels and quality of life (QoL) of patients with hematologic malignancies under treatment in an acute setting. We used external- and self-assessment instruments for distress. Additionally, we investigated the relation between distress and QoL as well as whether highly distressed patients differed from less distressed patients concerning their QoL.
Methods: A cross-sectional study with patients of the Medical Clinic II of the University Hospital Frankfurt was conducted. One hundred and nine patients were assessed with an expert rating scale and completed self-report questionnaires. Data were exploratively analyzed and group comparisons between patients who scored above the cut-off of the respective screening instruments and those who did not were conducted.
Results: Patients with hematologic malignancies experience high levels of distress and low QoL. Especially, role and social functioning are affected. Patients suffer most from fatigue, appetite loss, and insomnia. Using established cut-offs, all screening instruments were able to differentiate between patients regarding distress and QoL. Patients scoring above the cut-off were significantly more distressed and had a lower QoL. There was a medium-to-strong correlation between distress and QoL indicators.
Conclusion: Cancer-specific screening instruments seem to be able to identify treatment needs more specifically. They also allowed a better differentiation concerning QoL. The close link between distress and QoL needs to be recognized to enable a holistic approach to treatment and thereby optimize the quality of treatment.
Background: Autism spectrum disorder (ASD) is characterized by impaired social communication and interaction, and stereotyped, repetitive behaviour and sensory interests. To date, there is no effective medication that can improve social communication and interaction in ASD, and effect sizes of behaviour-based psychotherapy remain in the low to medium range. Consequently, there is a clear need for new treatment options. ASD is associated with altered activation and connectivity patterns in brain areas which process social information. Transcranial direct current stimulation (tDCS) is a technique that applies a weak electrical current to the brain in order to modulate neural excitability and alter connectivity. Combined with specific cognitive tasks, it allows to facilitate and consolidate the respective training effects. Therefore, application of tDCS in brain areas relevant to social cognition in combination with a specific cognitive training is a promising treatment approach for ASD. Methods: A phase-IIa pilot randomized, double-blind, sham-controlled, parallel-group clinical study is presented, which aims at investigating if 10 days of 20-min multi-channel tDCS stimulation of the bilateral tempo-parietal junction (TPJ) at 2.0 mA in combination with a computer-based cognitive training on perspective taking, intention and emotion understanding, can improve social cognitive abilities in children and adolescents with ASD. The main objectives are to describe the change in parent-rated social responsiveness from baseline (within 1 week before first stimulation) to post-intervention (within 7 days after last stimulation) and to monitor safety and tolerability of the intervention. Secondary objectives include the evaluation of change in parent-rated social responsiveness at follow-up (4 weeks after end of intervention), change in other ASD core symptoms and psychopathology, social cognitive abilities and neural functioning post-intervention and at follow-up in order to explore underlying neural and cognitive mechanisms. Discussion: If shown, positive results regarding change in parent-rated social cognition and favourable safety and tolerability of the intervention will confirm tDCS as a promising treatment for ASD core-symptoms. This may be a first step in establishing a new and cost-efficient intervention for individuals with ASD.
Beneficial acute effects of resistance exercise on cognitive functions may be modified by exercise intensity or by habitual physical activity. Twenty-six participants (9 female and 17 male; 25.5 ± 3.4 years) completed four resistance exercise interventions in a randomized order on separate days (≥48 h washout). The intensities were set at 60%, 75%, and 90% of the one repetition maximum (1RM). Three interventions had matched workloads (equal resistance*nrepetitions). One intervention applied 75% of the 1RM and a 50% reduced workload (resistance*nrepetitions = 50%). Cognitive attention (Trail Making Test A—TMTA), task switching (Trail Making Test B—TMTB), and working memory (Digit Reading Spans Backward) were assessed before and immediately after exercise. Habitual activity was assessed as MET hours per week using the International Physical Activity Questionnaire. TMTB time to completion was significantly shorter after exercise with an intensity of 60% 1RM and 75% 1RM and 100% workload. Friedman test indicated a significant effect of exercise intensity in favor of 60% 1RM. TMTA performance was significantly shorter after exercise with an intensity of 60% 1RM, 90% 1RM, and 75% 1RM (50% workload). Habitual activity with vigorous intensity correlated positively with the baseline TMTB and Digit Span Forward performance but not with pre- to post-intervention changes. Task switching, based on working memory, mental flexibility, and inhibition, was beneficially influenced by acute exercise with moderate intensity whereas attention performance was increased after exercise with moderate and vigorous intensity. The effect of regular activity had no impact on acute exercise effects.
Background: Increasingly, informal caregivers in Belgium care in group for an older patient. This study aimed to decrease the caregiver burden and to increase the well-being of caregivers and patients by supporting the needs of informal care groups of older patients (≥70 years).
Method: Through an online self-management tool, the groups were supported to make informed choices concerning the care for the older patient, taking into account the standards, values, concerns and needs of every caregiver and patient. A pre-post study was performed.
Results: Although patients and caregivers considered the self-management tool as useful and supportive, no clear evidence for decreased caregiver burden was found. There was a positive trend in group characteristics such as the distribution of tasks, communication and prevalence of conflicts. Caregivers also stated that they took more time for themselves, had less feelings of guilt and experienced less barriers to ask help.
Conclusion: Tailor-made support of informal care groups starts with facilitating and guiding a process to achieve consent within the group to optimise the care for the patient and also for the caregivers. With a shared vision and supported decisions, caregivers can enter into conversations with the professional caregiver to coordinate adjusted support regarding the care needs.
Background and purpose: The ENIGMA-EEG working group was established to enable large-scale international collaborations among cohorts that investigate the genetics of brain function measured with electroencephalography (EEG). In this perspective, we will discuss why analyzing the genetics of functional brain activity may be crucial for understanding how neurological and psychiatric liability genes affect the brain. Methods: We summarize how we have performed our currently largest genome-wide association study of oscillatory brain activity in EEG recordings by meta-analyzing the results across five participating cohorts, resulting in the first genome-wide significant hits for oscillatory brain function located in/near genes that were previously associated with psychiatric disorders. We describe how we have tackled methodological issues surrounding genetic meta-analysis of EEG features. We discuss the importance of harmonizing EEG signal processing, cleaning, and feature extraction. Finally, we explain our selection of EEG features currently being investigated, including the temporal dynamics of oscillations and the connectivity network based on synchronization of oscillations. Results: We present data that show how to perform systematic quality control and evaluate how choices in reference electrode and montage affect individual differences in EEG parameters. Conclusion: The long list of potential challenges to our large-scale meta-analytic approach requires extensive effort and organization between participating cohorts; however, our perspective shows that these challenges are surmountable. Our perspective argues that elucidating the genetic of EEG oscillatory activity is a worthwhile effort in order to elucidate the pathway from gene to disease liability.
22q11.2 Deletion Syndrome (22q11.2DS) is the most common microdeletion in humans, with a heterogenous clinical presentation including medical, behavioural and psychiatric conditions. Previous neuroimaging studies examining the neuroanatomical underpinnings of 22q11.2DS show alterations in cortical volume (CV), cortical thickness (CT) and surface area (SA). The aim of this study was to identify (1) the spatially distributed networks of differences in CT and SA in 22q11.2DS compared to controls, (2) their unique and spatial overlap, as well as (3) their relative contribution to observed differences in CV. Structural MRI scans were obtained from 62 individuals with 22q11.2DS and 57 age-and-gender-matched controls (aged 6–31). Using FreeSurfer, we examined differences in vertex-wise estimates of CV, CT and SA at each vertex, and compared the frequencies of vertices with a unique or overlapping difference for each morphometric feature. Our findings indicate that CT and SA make both common and unique contributions to volumetric differences in 22q11.2DS, and in some areas, their strong opposite effects mask differences in CV. By identifying the neuroanatomic variability in 22q11.2DS, and the separate contributions of CT and SA, we can start exploring the shared and distinct mechanisms that mediate neuropsychiatric symptoms across disorders, e.g. 22q11.2DS-related ASD and/or psychosis/schizophrenia.
Background: Autism spectrum disorder (“autism”) is a highly heterogeneous neurodevelopmental condition with few effective treatments for core and associated features. To make progress we need to both identify and validate neural markers that help to parse heterogeneity to tailor therapies to specific neurobiological profiles. Atypical hemispheric lateralization is a stable feature across studies in autism, but its potential as a neural stratification marker has not been widely examined. Methods: In order to dissect heterogeneity in lateralization in autism, we used the large EU-AIMS (European Autism Interventions—A Multicentre Study for Developing New Medications) Longitudinal European Autism Project dataset comprising 352 individuals with autism and 233 neurotypical control subjects as well as a replication dataset from ABIDE (Autism Brain Imaging Data Exchange) (513 individuals with autism, 691 neurotypical subjects) using a promising approach that moves beyond mean group comparisons. We derived gray matter voxelwise laterality values for each subject and modeled individual deviations from the normative pattern of brain laterality across age using normative modeling. Results: Individuals with autism had highly individualized patterns of both extreme right- and leftward deviations, particularly in language, motor, and visuospatial regions, associated with symptom severity. Language delay explained most variance in extreme rightward patterns, whereas core autism symptom severity explained most variance in extreme leftward patterns. Follow-up analyses showed that a stepwise pattern emerged, with individuals with autism with language delay showing more pronounced rightward deviations than individuals with autism without language delay. Conclusions: Our analyses corroborate the need for novel (dimensional) approaches to delineate the heterogeneous neuroanatomy in autism and indicate that atypical lateralization may constitute a neurophenotype for clinically meaningful stratification in autism.