Browsing by Author "Uhlmann, Anne"

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    A functional magnetic resonance imaging study of cognitive emotion regulation in relation to individual differences in self-esteem
    (2020) Swan, Freda Zoë; Groenewold, Nynke; Uhlmann, Anne; Stein, Dan
    Objectives Self-esteem may affect the processing and regulation of emotion. However, it is unclear whether differences in self-esteem are associated with changes in initial emotional appraisal or engagement of emotion regulation. I investigated whether individual differences in self-esteem predicted brain responses to negative emotional stimuli: 1) when they were viewed without intentional regulation; and 2) during downregulation using cognitive reappraisal. Thirdly, I investigated whether self-esteem predicted reappraisal success. Method Twenty-nine healthy adults (age M=47, SD=15; 16 female) performed a cognitive reappraisal emotion regulation task during fMRI scanning. Participants viewed and subsequently reappraised or attended to negative and neutral images. Trait self-esteem (Rosenberg Self-Esteem Scale) was included as a predictor in a whole-brain multiple regression analysis. Analyses were thresholded at p<.005, k>p20, p<.05 family-wise error (FWE)-corrected at cluster-level. The anterior cingulate cortex (ACC; BA32) and the dorsal prefrontal cortex (PFC; BA6) were a priori regions of interest (ROI), since both have previously been reported in fMRI studies of self-esteem and cognitive reappraisal. A post-hoc ROI analysis tested the correspondence of self-esteem-related ACC activation with findings from a meta-analysis of emotion regulation. Ratings of negative emotional intensity following reappraisal trials were subtracted from ratings following attend-negative trials to index reappraisal success. Results Self-esteem was associated with potentiated ACC ROI activation during viewing of negative, compared to neutral, images (MNI x, y, z = -6, 17, 38, k=43, punc=.001 at peak, pFWE=.368 at cluster-level). For reappraisal compared to attended negative images, self-esteem was positively associated with activation in the left posterior insula (MNI x, y, z = -30, -10, 17, k=30, punc<.001 at peak, pFWE=.959 at cluster-level) and negatively associated with activation in the mid cingulate cortex (MNI x, y, z = 3, -34, 35, k=50, punc=.001 at peak, pFWE=.805 at clusterlevel). However, only the post-hoc ACC ROI analysis was significant after multiple comparison correction (MNI x, y, z = -6, 23, 38, k=22, punc=.001 at peak, pFWE=.021 at clusterlevel). For reappraisal, self-esteem was not related to activation in the ACC or dorsal PFC ROIs. Trait self-esteem did not correlate with reappraisal success, r =.16, p =.208. Conclusion Trait self-esteem may affect recruitment of the ACC during initial emotional appraisal. This may reflect successful automatic emotion regulation for high self-esteem, consistent with the demonstrated spatial overlap with a meta-analytic emotion regulation cluster. While selfesteem may affect brain responsivity during cognitive reappraisal, the observed trends must be interpreted carefully, since the findings do not survive correction for multiple comparisons, and emotional outcomes of applying reappraisal do not differ as a function of self-esteem. Taken together, these findings suggest that high trait self-esteem may be advantageous for rapid automatic emotion regulation, but not deliberate cognitive reappraisal.
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    Modelling the pathophysiology of schizophrenia and methamphetamine-induced psychosis: A structural magnetic resonance imaging and cytokine study
    (2022) Blake, Lauren; Howells, Fleur M; Uhlmann, Anne; Stein, Dan J
    Background: There is overlap in the symptomatology and psychobiology of schizophrenia (SCZ) and methamphetamine-induced psychosis (MAP). In schizophrenia there are reports of significant associations of increased severity of psychotic symptoms with thinner frontal cortex and decreased hippocampus and amygdala volume, and there is evidence of increased TNF-α and interleukin (IL)-1β concentrations compared to healthy controls. However, no studies to date have 1) compared structural findings in SCZ and MAP, 2) investigated the associations of psychotic symptom severity and duration with brain volumes and cytokine concentrations in SCZ and MAP and 3) determined the effect of antipsychotic type on brain measures in SCZ compared to MAP. Methods: 36 patients with SCZ, 27 with MAP, and 32 healthy controls underwent clinical interview, structural magnetic resonance imaging (MRI) and phlebotomy. Symptom severity was assessed with the positive and negative symptom scales (PANSS). Volumes of the amygdala, hippocampus and basal ganglia and frontal cortical thickness and surface area were processed with FreeSurfer. TNF-α, IL-1β, -8, -12 and IFN-γ concentrations in serum, were assessed with a Luminex assay. ANOVAs were used to compare structural findings across groups, group differences for cytokine concentrations, number of psychotic episodes, symptom severity and to determine the effect of antipsychotics (AP) type on structural brain volumes and frontal cortical thickness in SCZ and MAP. Spearman's Rank and Pearson's correlations were used to determine associations of symptom severity, number of psychotic episodes and duration of illness with structural brain measures and cytokine concentrations. Results: 1) Decreased left amygdala volumes were reported in SCZ and MAP compared to CON, 2) increased right caudate and bilateral putamen and NAcc (nucleus accumbens) volumes were reported in SCZ compared to MAP and CON , with increased right pallidus volumes in SCZ compared to MAP, 3) decreased frontal cortical thickness was reported in SCZ and MAP compared to CON, 4) decreased frontal cortical surface area of the right pars opercularis and left pars triangularis was reported in SCZ compared to CON, 5) duration of illness was negatively correlated to decreased left amygdala volumes and frontal cortical thickness and surface area in SCZ, 6) there was a significant association between longer MA duration of use with decreased hippocampal and amygdala volumes and decreased frontal cortical thickness and surface areas in MAP, 7) significant effects of AP type were reported for frontal cortical thickness, 8) cytokine concentrations did not differ significantly between CON, SCZ and MAP and 9) number of psychotic episodes were greater in SCZ compared to MAP. Conclusions: These findings are consistent with the presence of both overlaps (e.g., in amygdala volume and frontal cortical thickness) and differences (e.g., in basal ganglia volume,) in the neurobiology of SCZ and MAP. It is noteworthy that longer illness duration is associated with decreased left amygdala volumes and frontal cortical thickness in SCZ and not MAP, suggesting that illness duration does not impart gray matter volume decreases in MAP. In MAP, MA use duration has significant associations with decreased left amygdala volumes, frontal cortical thickness and surface area in MAP. Decreased left amygdala volumes and frontal cortical thickness in both disorders suggest neurobiological overlap across these conditions, which may signify clinical importance in treatment of these conditions. Future studies involving magnetic resonance spectroscopy and imaging on the brain regions investigated in this study are encouraged to provide a better understanding of neuronal damage, neuroinflammatory processes and brain deficits of regions of interest in MAP and SCZ.
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    Neural correlates of deficits in affect regulation in methamphetamine abusers with and without a history of psychosis
    (2015) Uhlmann, Anne; Stein, Dan J; Meintjes, Ernesta M
    Methamphetamine dependence has been associated with neurological damage resulting in potentially long-lasting changes in cognitive-affective processes, a range of behavioral problems and psychiatric disorders, including psychosis. Poor emotional control and maladaptive social behaviors have been linked to abnormalities in brain function and structure. However, the links between alterations in neurocircuitries, affect dysregulation, and psychotic symptoms in methamphetamine dependence are yet to be fully elucidated. This project aimed to delineate emotion regulation capabilities as well as brain structure and function in methamphetamine-dependent individuals, patients with a history of methamphetamine-associated psychosis, and healthy adults. The four cross-sectional studies presented here investigated socio-emotional behaviour using self-report questionnaires and social cognition tasks; and assessed neural activation during incidental emotion regulation, measured in an affect labelling task as part of functional magnetic resonance imaging. Additionally, structural magnetic resonance imaging and diffusion tensor imaging were employed to determine grey matter and white matter structural abnormalities, respectively, and to correlate findings with the presence/absence of affect dysregulation and psychotic symptoms. Both methamphetamine-dependent groups showed deficits in emotion regulation abilities, as evidenced by increased levels of aggression, impulsivity, and emotion reactivity. Further, social cognition capacities, including recognising emotions and inferring mental states of others, were diminished in both groups, with greater functional decrements in patients with methamphetamine-associated psychosis. These patients further demonstrated grey matter loss in frontotemporal brain regions and hippocampi, as well as globally reduced white matter integrity, compared to methamphetamine-dependent individuals; and structural deficits in prefrontal and temporal brain regions were associated with impaired affect regulation. Frontolimbic hypoactivation during emotion perception further suggests a role of diminished emotional salience attribution in the pathogenesis of methamphetamine-associated psychosis. Whereas methamphetamine-dependent individuals displayed prefrontal hyperactivation during affect labelling, potentially reflecting a compensatory activation to sufficiently regulate affect, or suggesting a cognitive bias towards the negative facial emotions. Longitudinal data and prospective research designs are needed to address the issue of causality as well as the issue of changes in brain structure and function over time as addiction and related psychopathology progress. Therapies targeting socio-emotional perception and affect regulation skills ultimately may help improve social functioning and mitigate relapse rates.
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    Relationship between white matter changes and aggression in methamphetamine dependence
    (2015) Lederer, Katharina Johanna; Stein, Dan J; Uhlmann, Anne
    Background: Methamphetamine (MA) abuse is a growing problem in the world and especially in South Africa’s Western Cape. Amphetamine-type stimulants have become the second most widely abused illicit drugs worldwide. Admission data from substance abuse treatment centres in the Western Cape show the fastest increase for any drug ever noted in the country in MA related admissions. MA has neurotoxic effects on the brain leading, amongst other effects, to white matter (WM) changes. Moreover, increased levels of aggression are commonly found in individuals with MA abuse. Although behavioural deficits are well described, the underlying mechanisms are still poorly understood. While previous studies have examined WM abnormalities relating to cognitive impairment, none have investigated associations between WM integrity in individuals with MA dependence and aggression. Methods: Diffusion Tensor Imaging (DTI) was used to investigate WM changes in 40 individuals with MA dependence and 40 matched healthy control subjects. Aggression was measured with the Buss & Perry Questionnaire in 40 MA users and 36 controls. Two approaches to assess WM integrity in the brain were employed. First, whole brain voxel wise comparison across subjects using tract based spatial statistics (TBSS) in FSL was used. Fractional anisotropy (FA), mean diffusivity (MD), parallel diffusivity (λ║) and perpendicular diffusivity (λ┴) were compared between the two groups. Second, a region of interest (ROI) approach was used, which focused on three WM tracts in the frontal brain, commonly found to play a role in aggressive behaviour: (1) the genu of the corpus callosum (CC), (2) the cingulum and (3) the uncinate fasciculus.