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72 result(s) for "Hellemann Gerhard"
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Transcranial direct current stimulation (tDCS) in depression induces structural plasticity
Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique involving administration of well-tolerated electrical current to the brain through scalp electrodes. TDCS may improve symptoms in neuropsychiatric disorders, but mixed results from recent clinical trials underscore the need to demonstrate that tDCS can modulate clinically relevant brain systems over time in patients. Here, we analyzed longitudinal structural MRI data from a randomized, double-blind, parallel-design clinical trial in depression (NCT03556124, N = 59) to investigate whether serial tDCS individually targeted to the left dorso-lateral prefrontal cortex (DLPFC) can induce neurostructural changes. Significant (FWEc p  < 0.05) treatment-related gray matter changes were observed with active high-definition (HD) tDCS relative to sham tDCS within the left DLPFC stimulation target. No changes were observed with active conventional tDCS. A follow-up analysis within individual treatment groups revealed significant gray matter increases with active HD-tDCS in brain regions functionally connected with the stimulation target, including the bilateral DLPFC, bilateral posterior cingulate cortex, subgenual anterior cingulate cortex, and the right hippocampus, thalamus and left caudate brain regions. Integrity of blinding was verified, no significant differences in stimulation-related discomfort were observed between treatment groups, and tDCS treatments were not augmented by any other adjunct treatments. Overall, these results demonstrate that serial HD-tDCS leads to neurostructural changes at a predetermined brain target in depression and suggest that such plasticity effects may propagate over brain networks.
Cross-sectional observational study evaluating social brain health in HIV using a research domain criteria-based approach: a protocol
IntroductionSome people with HIV (PWH) experience brain changes that affect neurocognition, but little is known about how HIV impacts social cognition or related brain regions. Social cognition, the ability to perceive, understand and respond to social information, is important for maintaining relationships and quality of life. This article provides the protocol for the first comprehensive study examining social brain function in PWH and people without HIV (PWoH). With three aims, this study will: (1) examine neural circuits related to social cognition; (2) examine social cognitive performance across two social cognitive domains and (3) examine the role of social cognition in everyday social functioning.Methods and analysisReferred to as Social Brain Health Study in HIV Study, this cross-sectional study will enrol 105 PWH and 105 demographically matched PWoH aged 18–65 years. The study administers a comprehensive assessment battery across two visits within a 2-week period. Visit 1 includes behavioural measures of social cognition (Perceiving Social Cues and Understanding Others), neurocognition and social functioning (social network size and loneliness). Visit 2 involves functional MRI procedures with three social cognitive tasks designed to activate key brain regions (ie, fusiform face area, superior temporal gyrus, temporo-parietal junction, dorsal medial prefrontal cortex).Ethics and disseminationThis study was funded by the National Institute of Mental Health (MH139613) and approved by the Institutional Review Board of the University of Alabama at Birmingham (IRB-300013394). Data collection is ongoing. The first results are expected to be submitted for publication in 2030. Findings of this study will be published in peer-reviewed journals and presented at local, national and international conferences as well as patient organisations such as AIDS service organisations and community talks.
The relationship between sex and functional outcome in first-episode schizophrenia: the role of premorbid adjustment and insight
Studies that examined sex differences in first-episode patients consistently show that males compared to females have poor premorbid adjustment, earlier age of onset, worse clinical characteristics, and poorer outcomes. However, little is known about potential mediators that could explain these sex differences. Our sample consisted of 137 individuals with first episode schizophrenia (males, = 105; 77%) with a mean age of 22.1(s.d. = 4.1) years and mean education of 12.5(s.d. = 1.7) years. At entry, patients were within 2 years of their first psychotic episode onset. Baseline assessments were conducted for premorbid adjustment, symptoms, cognitive functioning, insight, and at 6-months for role and social functioning. Males as compared to females had poorer premorbid adjustment across several key developmental periods ( < 0.01), an earlier age of onset [M = 20.3(3.3) 22.8(5.6), = 0.002], more negative symptoms ( = 0.044), poorer insight ( = 0.031), and poorer baseline and 6-month role ( = 0.002) and social functioning ( = 0.034). Several of these variables in which males showed impairment were significant predictors of 6-month role and social functioning. Premorbid adjustment and insight mediated the relationship between sex and role and social functioning at 6-months, but not negative symptoms. Males compared to females were at lower levels across several key premorbid and clinical domains which are strongly associated with functional outcome supporting the hypothesis that males might have a more disabling form of schizophrenia. The relationship between sex with role and social functioning was mediated through premorbid adjustment and insight suggesting pathways for understanding why females might have a less disabling form of schizophrenia.
Hippocampal subregions and networks linked with antidepressant response to electroconvulsive therapy
Electroconvulsive therapy (ECT) has been repeatedly linked to hippocampal plasticity. However, it remains unclear what role hippocampal plasticity plays in the antidepressant response to ECT. This magnetic resonance imaging (MRI) study tracks changes in separate hippocampal subregions and hippocampal networks in patients with depression (n = 44, 23 female) to determine their relationship, if any, with improvement after ECT. Voxelwise analyses were restricted to the hippocampus, amygdala, and parahippocampal cortex, and applied separately for responders and nonresponders to ECT. In analyses of arterial spin-labeled (ASL) MRI, nonresponders exhibited increased cerebral blood flow (CBF) in bilateral anterior hippocampus, while responders showed CBF increases in right middle and left posterior hippocampus. In analyses of gray matter volume (GMV) using T1-weighted MRI, GMV increased throughout bilateral hippocampus and surrounding tissue in nonresponders, while responders showed increased GMV in right anterior hippocampus only. Using CBF loci as seed regions, BOLD-fMRI data from healthy controls (n = 36, 19 female) identified spatially separable neurofunctional networks comprised of different brain regions. In graph theory analyses of these networks, functional connectivity within a hippocampus-thalamus-striatum network decreased only in responders after two treatments and after index. In sum, our results suggest that the location of ECT-related plasticity within the hippocampus may differ according to antidepressant outcome, and that larger amounts of hippocampal plasticity may not be conducive to positive antidepressant response. More focused targeting of hippocampal subregions and/or circuits may be a way to improve ECT outcome.
Depression treatment response to ketamine: sex-specific role of interleukin-8, but not other inflammatory markers
Inflammation plays a role in depression pathophysiology and treatment response, with effects varying by sex and therapeutic modality. Lower levels of interleukin(IL)-8 predict depression response to antidepressant medication and to electroconvulsive therapy (ECT), although ECT effects are specific to females. Whether IL-8 predicts depression response to ketamine and in a sex-specific manner is not known. Here, depressed patients (n = 46; female, n = 17) received open label infusion of ketamine (0.5 mg/kg over 40 min; NCT02165449). Plasma levels of IL-8 were evaluated at baseline and post-treatment. Baseline levels of IL-8 had a trending association with response to ketamine, depending upon sex (responder status × sex interaction: p = 0.096), in which lower baseline levels of IL-8 in females (p = 0.095) but not males (p = 0.96) trended with treatment response. Change in levels of IL-8 from baseline to post-treatment differed significantly by responder status (defined as ≥50% reduction in Hamilton Depression Rating Scale [HAM-D] Score), depending upon sex (responder status × sex × time interaction: F(1,42)=6.68, p = 0.01). In addition, change in IL-8 interacted with sex to predict change in HAM-D score (β = -0.63, p = 0.003); increasing IL-8 was associated with decreasing HAM-D score in females (p = 0.08) whereas the inverse was found in males (p = 0.02). Other inflammatory markers (IL-6, IL-10, tumor necrosis factor-α, C-reactive protein) were explored with no significant relationships identified. Given these preliminary findings, further evaluation of sex differences in the relationship between IL-8 and treatment response is warranted to elucidate mechanisms of response and aid in the development of personalized approaches to depression treatment.
Parsing components of auditory predictive coding in schizophrenia using a roving standard mismatch negativity paradigm
Mismatch negativity (MMN) is an event-related potential (ERP) component reflecting auditory predictive coding. Repeated standard tones evoke increasing positivity ('repetition positivity'; RP), reflecting strengthening of the standard's memory trace and the prediction it will recur. Likewise, deviant tones preceded by more standard repetitions evoke greater negativity ('deviant negativity'; DN), reflecting stronger prediction error signaling. These memory trace effects are also evident in MMN difference wave. Here, we assess group differences and test-retest reliability of these indices in schizophrenia patients (SZ) and healthy controls (HC). Electroencephalography was recorded twice, 2 weeks apart, from 43 SZ and 30 HC, during a roving standard paradigm. We examined ERPs to the third, eighth, and 33rd standards (RP), immediately subsequent deviants (DN), and the corresponding MMN. Memory trace effects were assessed by comparing amplitudes associated with the three standard repetition trains. Compared with controls, SZ showed reduced MMNs and DNs, but normal RPs. Both groups showed memory trace effects for RP, MMN, and DN, with a trend for attenuated DNs in SZ. Intraclass correlations obtained via this paradigm indicated good-to-moderate reliabilities for overall MMN, DN and RP, but moderate to poor reliabilities for components associated with short, intermediate, and long standard trains, and poor reliability of their memory trace effects. MMN deficits in SZ reflected attenuated prediction error signaling (DN), with relatively intact predictive code formation (RP) and memory trace effects. This roving standard MMN paradigm requires additional development/validation to obtain suitable levels of reliability for use in clinical trials.
Functional brain mapping of body size estimation using a 3D avatar
Body size estimation—the ability to judge the size and shape of one’s own body—is a key perceptual component of body image. However, its neural basis, and the basis for inter-individual differences in accuracy, remain poorly understood, partly due to limitations in existing assessment tools. We used an adapted, fMRI-compatible version of Somatomap 3D, an interactive task in which participants manipulate a rotatable 3D avatar by adjusting the size and shape of 26 individual body parts to match their perceived body. Twenty-eight healthy male and female adults completed the task during fMRI. Brain activity in a priori regions of interest from previous studies of body processing was modeled using a general linear model incorporating event-specific parameters and parametric modulators related to task performance. Inter-individual differences in body size estimation accuracy were calculated using multidimensional scaling of body part estimation errors, and scores were correlated with BOLD signal eigenvariates from regions of interest. Task engagement was associated with significant activation in hypothesized body-selective and multisensory regions, including bilateral extrastriate body area, right fusiform body area, right superior parietal lobule, and bilateral premotor cortex. Multidimensional scaling identified a primary subdimension reflecting distortions in body part girths, which was significantly associated with neural responses in bilateral superior parietal lobule. No other brain regions showed significant associations with inter-individual differences in estimation accuracy. These results suggest that body size estimation engages a distributed network of visual, motor, and parietal regions. Among these, only the superior parietal lobule showed a significant association with inter-individual variation in body size estimation accuracy for body part girths, supporting its role as a candidate neural substrate for altered body representation in psychiatric conditions such as eating disorders and body dysmorphic disorder.
Sex differences in tobacco withdrawal and responses to smoking reduced-nicotine cigarettes in young smokers
Rationale Policies that establish a standard for reduced nicotine content in cigarettes can decrease the prevalence of smoking in the USA. Cigarettes with nicotine yields as low as 0.05 mg produce substantial occupancy of nicotinic acetylcholine receptors (26%), but women and men respond differently to these cigarettes. Objective This study aimed to measure responses to smoking cigarettes that varied widely in nicotine yields, investigating whether sex differences in the effects on craving, withdrawal, and affect would be observed at even lower nicotine yields than previously studied, and in young smokers. Methods Overnight abstinent young smokers (23 men, 23 women, mean age 22.18) provided self-reports of craving, withdrawal, and affect before and after smoking cigarettes with yields of 0.027, 0.110, 0.231, or 0.763 mg nicotine, and evaluated characteristics of each cigarette. Results Compared to abstinent young men, abstinent young women reported greater negative affect, psychological withdrawal, and sedation, all of which were relieved equally by all cigarettes. Men but not women reported greater craving reduction, perceived nicotine content, and cigarette liking with increasing nicotine dose. Conclusions Men may experience less smoking-related relief of craving, and enjoy cigarettes less, if nicotine yields are reduced to very low levels. Conversely, women respond equally well to cigarettes with nicotine yields as low as 0.027 mg as to cigarettes with nicotine yields 28-fold higher (0.763 mg). These differences are relevant for policy regarding reduced nicotine in cigarettes and may influence the efficacy and acceptability of reduced-nicotine cigarettes as smoking cessation aids.
The effects of age and sex on cognitive impairment in schizophrenia: Findings from the Consortium on the Genetics of Schizophrenia (COGS) study
Recently emerging evidence indicates accelerated age-related changes in the structure and function of the brain in schizophrenia, raising a question about its potential consequences on cognitive function. Using a large sample of schizophrenia patients and controls and a battery of tasks across multiple cognitive domains, we examined whether patients show accelerated age-related decline in cognition and whether an age-related effect differ between females and males. We utilized data of 1,415 schizophrenia patients and 1,062 healthy community collected by the second phase of the Consortium on the Genetics of Schizophrenia (COGS-2). A battery of cognitive tasks included the Letter-Number Span Task, two forms of the Continuous Performance Test, the California Verbal Learning Test, Second Edition, the Penn Emotion Identification Test and the Penn Facial Memory Test. The effect of age and gender on cognitive performance was examined with a general linear model. We observed age-related changes on most cognitive measures, which was similar between males and females. Compared to controls, patients showed greater deterioration in performance on attention/vigilance and greater slowness of processing social information with increasing age. However, controls showed greater age-related changes in working memory and verbal memory compared to patients. Age-related changes (η2p of 0.001 to .008) were much smaller than between-group differences (η2p of 0.005 to .037). This study found that patients showed continued decline of cognition on some domains but stable impairment or even less decline on other domains with increasing age. These findings indicate that age-related changes in cognition in schizophrenia are subtle and not uniform across multiple cognitive domains.
Quantifying body size estimation accuracy and body dissatisfaction in body dysmorphic disorder using a digital avatar
A core feature of body dysmorphic disorder (BDD) is body image disturbance. Many with BDD misperceive and are dissatisfied with the sizes and shapes of body parts, but detailed quantification and analysis of this has not yet been performed. To address this gap, we applied Somatomap 3D, a digital avatar tool, to quantify body image disturbances by assessing body size estimation (BSE) accuracy and body dissatisfaction. Sixty-one adults (31 with BDD, 30 healthy controls) created avatars to reflect their perceived current body and ideal body by altering 23 body part sizes and lengths using Somatomap 3D. Physical measurements of corresponding body parts were recorded for comparison. BSE accuracy (current minus actual) and body dissatisfaction (ideal minus current) were compared between groups and in relation to BDD symptom severity using generalized estimating equations. Individuals with BDD significantly over- and under-estimated certain body parts compared to healthy controls. Individuals with BDD overall desired significantly thinner body parts compared to healthy controls. Moreover, those with worse BSE accuracy had greater body dissatisfaction and poorer insight. In sum, this digital avatar tool revealed disturbances in body image in individuals with BDD that may have perceptual and cognitive/affective components. [Display omitted] •Those with body dysmorphic disorder differ in estimating specific body part sizes.•Those with body dysmorphic disorder tend to desire smaller body parts.•Body size estimation accuracy is related to body dissatisfaction.•Those with worse body size estimation accuracy have poorer insight.•A digital avatar can quantify body image disturbances in body dysmorphic disorder.