RESUMO
Real-time fMRI neurofeedback is an increasingly popular neuroimaging technique that allows an individual to gain control over his/her own brain signals, which can lead to improvements in behavior in healthy participants as well as to improvements of clinical symptoms in patient populations. However, a considerably large ratio of participants undergoing neurofeedback training do not learn to control their own brain signals and, consequently, do not benefit from neurofeedback interventions, which limits clinical efficacy of neurofeedback interventions. As neurofeedback success varies between studies and participants, it is important to identify factors that might influence neurofeedback success. Here, for the first time, we employed a big data machine learning approach to investigate the influence of 20 different design-specific (e.g. activity vs. connectivity feedback), region of interest-specific (e.g. cortical vs. subcortical) and subject-specific factors (e.g. age) on neurofeedback performance and improvement in 608 participants from 28 independent experiments. With a classification accuracy of 60% (considerably different from chance level), we identified two factors that significantly influenced neurofeedback performance: Both the inclusion of a pre-training no-feedback run before neurofeedback training and neurofeedback training of patients as compared to healthy participants were associated with better neurofeedback performance. The positive effect of pre-training no-feedback runs on neurofeedback performance might be due to the familiarization of participants with the neurofeedback setup and the mental imagery task before neurofeedback training runs. Better performance of patients as compared to healthy participants might be driven by higher motivation of patients, higher ranges for the regulation of dysfunctional brain signals, or a more extensive piloting of clinical experimental paradigms. Due to the large heterogeneity of our dataset, these findings likely generalize across neurofeedback studies, thus providing guidance for designing more efficient neurofeedback studies specifically for improving clinical neurofeedback-based interventions. To facilitate the development of data-driven recommendations for specific design details and subpopulations the field would benefit from stronger engagement in open science research practices and data sharing.
Assuntos
Neuroimagem Funcional , Aprendizado de Máquina , Imageamento por Ressonância Magnética , Neurorretroalimentação , Adulto , HumanosRESUMO
BACKGROUND: Moral injury (MI) is consistently associated with adverse mental health outcomes, including the development of posttraumatic stress disorder (PTSD) and suicidality. METHODS: We investigated neural activation patterns associated with MI event recall using functional magnetic resonance imaging in participants with military and public safety-related PTSD, relative to civilian MI-exposed controls. RESULTS: MI recall in the PTSD as compared to control group was associated with increased neural activation among salience network nodes involved in viscerosensory processing and hyperarousal (right posterior insula, dorsal anterior cingulate cortex; dACC), regions involved in defensive responding (left postcentral gyrus), and areas responsible for top-down cognitive control of emotions (left dorsolateral prefrontal cortex; dlPFC). Within the PTSD group, measures of state and trait shame correlated negatively with activity among default mode network regions associated with self-related processing and moral cognition (dorsomedial prefrontal cortex; dmPFC) and salience network regions associated with viscerosensory processing (left posterior insula), respectively. CONCLUSIONS: These findings suggest that MI event processing is altered in military and public safety-related PTSD, relative to MI-exposed controls. Here, it appears probable that as individuals with PTSD recall their MI event, they experience a surge of blame-related processing of bodily sensations within salience network regions, including the right posterior insula and the dACC, which in turn, prompt regulatory strategies at the level of the left dlPFC aimed at increasing cognitive control and inhibiting emotional affect. These results are consistent with previous findings showing enhanced sensory processing and altered top-down control in PTSD samples during autobiographical memory recall.
Assuntos
Transtornos de Estresse Pós-Traumáticos , Encéfalo/diagnóstico por imagem , Emoções , Humanos , Imageamento por Ressonância Magnética , Rememoração Mental , Vergonha , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagemRESUMO
Neurofeedback has begun to attract the attention and scrutiny of the scientific and medical mainstream. Here, neurofeedback researchers present a consensus-derived checklist that aims to improve the reporting and experimental design standards in the field.
Assuntos
Lista de Checagem/métodos , Neurorretroalimentação/métodos , Adulto , Consenso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Revisão da Pesquisa por Pares , Projetos de Pesquisa/normas , Participação dos InteressadosRESUMO
Positive-social emotions mediate one's cognitive performance, mood, well-being, and social bonds, and represent a critical variable within therapeutic settings. It has been shown that the upregulation of positive emotions in social situations is associated with increased top-down signals that stem from the prefrontal cortices (PFC) which modulate bottom-up emotional responses in the amygdala. However, it remains unclear if positive-social emotion upregulation of the amygdala occurs directly through the dorsomedial PFC (dmPFC) or indirectly linking the bilateral amygdala with the dmPFC via the subgenual anterior cingulate cortex (sgACC), an area which typically serves as a gatekeeper between cognitive and emotion networks. We performed functional MRI (fMRI) experiments with and without effortful positive-social emotion upregulation to demonstrate the functional architecture of a network involving the amygdala, the dmPFC, and the sgACC. We found that effortful positive-social emotion upregulation was associated with an increase in top-down connectivity from the dmPFC on the amygdala via both direct and indirect connections with the sgACC. Conversely, we found that emotion processes without effortful regulation increased network modulation by the sgACC and amygdala. We also found that more anxious individuals with a greater tendency to suppress emotions and intrusive thoughts, were likely to display decreased amygdala, dmPFC, and sgACC activity and stronger connectivity strength from the sgACC onto the left amygdala during effortful emotion upregulation. Analyzed brain network suggests a more general role of the sgACC in cognitive control and sheds light on neurobiological informed treatment interventions.
Assuntos
Tonsila do Cerebelo/fisiologia , Conectoma , Regulação Emocional/fisiologia , Giro do Cíngulo/fisiologia , Rede Nervosa/fisiologia , Córtex Pré-Frontal/fisiologia , Percepção Social , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Imagem Ecoplanar , Feminino , Giro do Cíngulo/diagnóstico por imagem , Humanos , Masculino , Rede Nervosa/diagnóstico por imagem , Córtex Pré-Frontal/diagnóstico por imagem , Percepção Visual/fisiologia , Adulto JovemRESUMO
BACKGROUND: The field of psychiatry would benefit significantly from developing objective biomarkers that could facilitate the early identification of heterogeneous subtypes of illness. Critically, although machine learning pattern recognition methods have been applied recently to predict many psychiatric disorders, these techniques have not been utilized to predict subtypes of posttraumatic stress disorder (PTSD), including the dissociative subtype of PTSD (PTSD + DS). METHODS: Using Multiclass Gaussian Process Classification within PRoNTo, we examined the classification accuracy of: (i) the mean amplitude of low-frequency fluctuations (mALFF; reflecting spontaneous neural activity during rest); and (ii) seed-based amygdala complex functional connectivity within 181 participants [PTSD (n = 81); PTSD + DS (n = 49); and age-matched healthy trauma-unexposed controls (n = 51)]. We also computed mass-univariate analyses in order to observe regional group differences [false-discovery-rate (FDR)-cluster corrected p < 0.05, k = 20]. RESULTS: We found that extracted features could predict accurately the classification of PTSD, PTSD + DS, and healthy controls, using both resting-state mALFF (91.63% balanced accuracy, p < 0.001) and amygdala complex connectivity maps (85.00% balanced accuracy, p < 0.001). These results were replicated using independent machine learning algorithms/cross-validation procedures. Moreover, areas weighted as being most important for group classification also displayed significant group differences at the univariate level. Here, whereas the PTSD + DS group displayed increased activation within emotion regulation regions, the PTSD group showed increased activation within the amygdala, globus pallidus, and motor/somatosensory regions. CONCLUSION: The current study has significant implications for advancing machine learning applications within the field of psychiatry, as well as for developing objective biomarkers indicative of diagnostic heterogeneity.
Assuntos
Tonsila do Cerebelo/diagnóstico por imagem , Transtornos Dissociativos/diagnóstico por imagem , Aprendizado de Máquina , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Adulto , Tonsila do Cerebelo/fisiopatologia , Mapeamento Encefálico/métodos , Estudos de Casos e Controles , Transtornos Dissociativos/fisiopatologia , Emoções , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Descanso , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Adulto JovemRESUMO
Posttraumatic stress disorder (PTSD) has been associated with a disturbance in neural intrinsic connectivity networks (ICN), including the central executive network (CEN), default mode network (DMN), and salience network (SN). Here, we conducted a preliminary investigation examining potential changes in ICN recruitment as a function of real-time fMRI neurofeedback (rt-fMRI-NFB) during symptom provocation where we targeted the downregulation of neural response within the amygdala-a key region-of-interest in PTSD neuropathophysiology. Patients with PTSD (n = 14) completed three sessions of rt-fMRI-NFB with the following conditions: (a) regulate: decrease activation in the amygdala while processing personalized trauma words; (b) view: process trauma words while not attempting to regulate the amygdala; and (c) neutral: process neutral words. We found that recruitment of the left CEN increased over neurofeedback runs during the regulate condition, a finding supported by increased dlPFC activation during the regulate as compared to the view condition. In contrast, DMN task-negative recruitment was stable during neurofeedback runs, albeit was the highest during view conditions and increased (normalized) during rest periods. Critically, SN recruitment was high for both the regulate and the view conditions, a finding potentially indicative of CEN modality switching, adaptive learning, and increasing threat/defense processing in PTSD. In conclusion, this study provides provocative, preliminary evidence that downregulation of the amygdala using rt-fMRI-NFB in PTSD is associated with dynamic changes in ICN, an effect similar to those observed using EEG modalities of neurofeedback.
Assuntos
Tonsila do Cerebelo/fisiopatologia , Imageamento por Ressonância Magnética , Neurorretroalimentação , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/terapia , Tonsila do Cerebelo/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Neurorretroalimentação/métodos , Dados Preliminares , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Percepção Visual/fisiologiaRESUMO
Dissociative experiences have been associated with increased disease severity, chronicity, and, in some cases, reduced treatment response across trauma-related and other psychiatric disorders. A better understanding of the neurobiological mechanisms through which dissociative experiences occur may assist in identifying novel pharmacological and non-pharmacological treatment approaches. Here, we review emerging work on the dissociative subtype of posttraumatic stress disorder (PTSD), and other trauma-related disorders providing evidence for two related overarching neurobiological models of dissociation, the defense cascade model of dissociation and Mobb's threat detection model. In particular, we review neuroimaging studies highlighting alterations in functional connectivity of key brain regions associated with these models, including connectivity between the prefrontal cortex, the amygdala and its complexes, the insula, and the periaqueductal gray. Work implicating the kappa-opioid and endocannabinoid systems in trauma-related dissociative experiences is also reviewed. Finally, we hypothesize mechanisms by which pharmacological modulation of these neurochemical systems may serve as promising transdiagnostic treatment modalities for individuals experiencing clinically significant levels of dissociation. Specifically, whereas kappa-opioid receptor antagonists may serve as a pharmacological vehicle for the selective targeting of dissociative symptoms and associated emotion overmodulation in the dissociative subtype of posttraumatic stress disorder and transdiagnostically, modulation of the endocannabinoid system may reduce symptoms associated with emotional undermodulation of the fight or flight components of the defense cascade model.
Assuntos
Analgésicos Opioides/efeitos adversos , Canabinoides/efeitos adversos , Transtornos Dissociativos/fisiopatologia , Transtornos Dissociativos/psicologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Pesquisa Translacional Biomédica , Encéfalo/fisiopatologia , Transtornos Dissociativos/induzido quimicamente , Transtornos Dissociativos/terapia , Emoções/efeitos dos fármacos , Humanos , Modelos Neurológicos , Neurobiologia , Transtornos de Estresse Pós-Traumáticos/induzido quimicamente , Transtornos de Estresse Pós-Traumáticos/terapiaRESUMO
OBJECTIVES: Although dysfunctional emotion regulatory capacities are increasingly recognized as contributing to posttraumatic stress disorder (PTSD), little work has sought to identify biological markers of this vulnerability. Heart rate variability (HRV) is a promising biomarker that, together with neuroimaging, may assist in gaining a deeper understanding of emotion dysregulation in PTSD. The objective of the present study was, therefore, to characterize autonomic response patterns, and their related neuronal patterns in individuals with PTSD at rest. METHODS: PTSD patients (N = 57) and healthy controls (N = 41) underwent resting-state fMRI. Connectivity patterns of key regions within the central autonomic network (CAN)-including the ventromedial prefrontal cortex (vmPFC), amygdala, and periaqueductal gray (PAG)-were examined using a seed-based approach. Observed connectivity patterns were then correlated to resting HRV. RESULTS: In contrast to controls, individuals with PTSD exhibited lower HRV. In addition, whereas controls engaged a localized connectivity pattern of CAN-related brain regions, in PTSD, key CAN regions were associated with widespread connectivity patterns in regions related to emotional reactivity (vmPFC and amygdala to insular cortex and lentiform nucleus; PAG to insula) and motor readiness (vmPFC and amygdala to precentral gyrus; PAG to precentral gyrus and cerebellum). Critically, whereas CAN connectivity in controls was strongly related to higher HRV (insula, mPFC, superior frontal cortex, thalamus), HRV covariation was absent in PTSD subjects. CONCLUSIONS: This study provides the first evidence for a specific psychophysiological-neuronal profile in PTSD individuals characterized by lower resting HRV and a lack of HRV covariation with CAN-related brain connectivity. Hum Brain Mapp 38:27-40, 2017. © 2016 Wiley Periodicals, Inc.
Assuntos
Doenças do Sistema Nervoso Autônomo/etiologia , Encéfalo/diagnóstico por imagem , Vias Neurais/fisiologia , Transtornos de Estresse Pós-Traumáticos/complicações , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Adulto , Sistema Nervoso Autônomo/diagnóstico por imagem , Sistema Nervoso Autônomo/fisiopatologia , Doenças do Sistema Nervoso Autônomo/diagnóstico por imagem , Encéfalo/irrigação sanguínea , Encéfalo/patologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Descanso , Estudos Retrospectivos , Adulto JovemRESUMO
Amygdala dysregulation has been shown to be central to the pathophysiology of posttraumatic stress disorder (PTSD) representing a critical treatment target. Here, amygdala downregulation was targeted using real-time fMRI neurofeedback (rt-fMRI-nf) in patients with PTSD, allowing us to examine further the regulation of emotional states during symptom provocation. Patients (n = 10) completed three sessions of rt-fMRI-nf with the instruction to downregulate activation in the amygdala, while viewing personalized trauma words. Amygdala downregulation was assessed by contrasting (a) regulate trials, with (b) viewing trauma words and not attempting to regulate. Training was followed by one transfer run not involving neurofeedback. Generalized psychophysiological interaction (gPPI) and dynamic causal modeling (DCM) analyses were also computed to explore task-based functional connectivity and causal structure, respectively. It was found that PTSD patients were able to successfully downregulate both right and left amygdala activation, showing sustained effects within the transfer run. Increased activation in the dorsolateral and ventrolateral prefrontal cortex (PFC), regions related to emotion regulation, was observed during regulate as compared with view conditions. Importantly, activation in the PFC, rostral anterior cingulate cortex, and the insula, were negatively correlated to PTSD dissociative symptoms in the transfer run. Increased functional connectivity between the amygdala- and both the dorsolateral and dorsomedial PFC was found during regulate, as compared with view conditions during neurofeedback training. Finally, our DCM analysis exploring directional structure suggested that amygdala downregulation involves both top-down and bottom-up information flow with regard to observed PFC-amygdala connectivity. This is the first demonstration of successful downregulation of the amygdala using rt-fMRI-nf in PTSD, which was critically sustained in a subsequent transfer run without neurofeedback, and corresponded to increased connectivity with prefrontal regions involved in emotion regulation during the intervention. Hum Brain Mapp 38:541-560, 2017. © 2016 Wiley Periodicals, Inc.
Assuntos
Tonsila do Cerebelo/fisiopatologia , Encéfalo/diagnóstico por imagem , Emoções/fisiologia , Imageamento por Ressonância Magnética , Transtornos de Estresse Pós-Traumáticos/patologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Análise de Variância , Retroalimentação Sensorial/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Oxigênio/sangue , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagemRESUMO
OBJECTIVE: Posttraumatic stress disorder (PTSD) is associated with decreased top-down emotion modulation from medial prefrontal cortex (mPFC) regions, a pathophysiology accompanied by hyperarousal and hyperactivation of the amygdala. By contrast, PTSD patients with the dissociative subtype (PTSD + DS) often exhibit increased mPFC top-down modulation and decreased amygdala activation associated with emotional detachment and hypoarousal. Crucially, PTSD and PTSD + DS display distinct functional connectivity within the PFC, amygdala complexes, and the periaqueductal gray (PAG), a region related to defensive responses/emotional coping. However, differences in directed connectivity between these regions have not been established in PTSD, PTSD + DS, or controls. METHODS: To examine directed (effective) connectivity among these nodes, as well as group differences, we conducted resting-state stochastic dynamic causal modeling (sDCM) pairwise analyses of coupling between the ventromedial (vm)PFC, the bilateral basolateral and centromedial (CMA) amygdala complexes, and the PAG, in 155 participants (PTSD [n = 62]; PTSD + DS [n = 41]; age-matched healthy trauma-unexposed controls [n = 52]). RESULTS: PTSD was characterized by a pattern of predominant bottom-up connectivity from the amygdala to the vmPFC and from the PAG to the vmPFC and amygdala. Conversely, PTSD + DS exhibited predominant top-down connectivity between all node pairs (from the vmPFC to the amygdala and PAG, and from the amygdala to the PAG). Interestingly, the PTSD + DS group displayed the strongest intrinsic inhibitory connections within the vmPFC. CONCLUSIONS: These results suggest the contrasting symptom profiles of PTSD and its dissociative subtype (hyper- vs. hypo-emotionality, respectively) may be driven by complementary changes in directed connectivity corresponding to bottom-up defensive fear processing versus enhanced top-down regulation. Hum Brain Mapp 38:5551-5561, 2017. © 2017 Wiley Periodicals, Inc.
Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiopatologia , Transtornos Dissociativos/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Adulto , Adultos Sobreviventes de Eventos Adversos na Infância , Teorema de Bayes , Encéfalo/diagnóstico por imagem , Transtornos Dissociativos/diagnóstico por imagem , Medo/fisiologia , Feminino , Humanos , Masculino , Análise Multivariada , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Transtornos de Estresse Pós-Traumáticos/psicologiaRESUMO
BACKGROUND: Post-traumatic stress disorder can be viewed as a memory disorder, with trauma-related flashbacks being a core symptom. Given the central role of the hippocampus in autobiographical memory, surprisingly, there is mixed evidence concerning altered hippocampal functional connectivity in PTSD. We shed light on this discrepancy by considering the distinct roles of the anterior versus posterior hippocampus and examine how this distinction may map onto whole-brain resting-state functional connectivity patterns among those with and without PTSD. METHODS: We first assessed whole-brain between-group differences in the functional connectivity profiles of the anterior and posterior hippocampus within a publicly available data set of resting-state fMRI data from 31 male Vietnam war veterans diagnosed with PTSD (mean age = 67.6 years, sd = 2.3) and 29 age-matched combat-exposed male controls (age = 69.1 years, sd = 3.5). Next, the connectivity patterns of each subject within the PTSD group were correlated with their PTSD symptom scores. Finally, the between-group differences in whole-brain functional connectivity profiles discovered for the anterior and posterior hippocampal seeds were used to prescribe post-hoc ROIs, which were then used to perform ROI-to-ROI functional connectivity and graph-theoretic analyses. RESULTS: The PTSD group showed increased functional connectivity of the anterior hippocampus with affective brain regions (anterior/posterior insula, orbitofrontal cortex, temporal pole) and decreased functional connectivity of the anterior/posterior hippocampus with regions involved in processing bodily self-consciousness (supramarginal gyrus). Notably, decreased anterior hippocampus connectivity with the posterior cingulate cortex/precuneus was associated with increased PTSD symptom severity. The left anterior hippocampus also emerged as a central locus of abnormal functional connectivity, with graph-theoretic measures suggestive of a more central hub-like role for this region in those with PTSD compared to trauma-exposed controls. CONCLUSIONS: Our results highlight that the anterior hippocampus plays a critical role in the neurocircuitry underlying PTSD and underscore the importance of the differential roles of hippocampal sub-regions in serving as biomarkers of PTSD. Future studies should investigate whether the differential patterns of functional connectivity stemming from hippocampal sub-regions is observed in PTSD populations other than older war veterans.
Assuntos
Transtornos de Estresse Pós-Traumáticos , Humanos , Masculino , Idoso , Encéfalo , Mapeamento Encefálico , Imageamento por Ressonância Magnética/métodos , Hipocampo/diagnóstico por imagemRESUMO
BACKGROUND: Posttraumatic stress disorder (PTSD) has been found to be associated with emotion under-modulation from the prefrontal cortex and a breakdown of the top-down control of cognition and emotion. Novel adjunct therapies such as neurofeedback (NFB) have been shown to normalize aberrant neural circuits that underlie PTSD psychopathology at rest. However, little evidence exists for NFB-linked neural improvements under emotionally relevant cognitive load. The current study sought to address this gap by examining the effects of alpha-down NFB in the context of an emotional n-back task. METHODS: We conducted a 20-week double-blind randomized, sham-controlled trial of alpha-down NFB and collected neuroimaging data before and after the NFB protocol. Participants performed an emotional 1-back and 2-back working memory task, with interleaved trauma-neutral and trauma-relevant cues in the fMRI scanner. Data from 35 participants with a primary diagnosis of PTSD were analyzed in this study (n = 18 in the experimental group undergoing alpha-down NFB, n = 17 in the sham-control group). RESULTS: Firstly, within-group analyses showed clinically significant reductions in PTSD symptom severity scores at the post-intervention timepoint and 3-month follow-up for the experimental group, and not for the sham-control group. The neuroimaging analyses revealed that alpha-down NFB enhanced engagement of top-down cognitive and emotional control centers, such as the dorsolateral prefrontal cortex (dlPFC), and improved integration of the anterior and posterior parts of the default mode network (DMN). Finally, our results also indicate that increased alpha-down NFB performance correlated with increased activity in brain regions involved in top-down control and bodily consciousness/embodied processing of self (TPJ and posterior insula). CONCLUSION: This is the first study to provide mechanistic insights into how NFB may normalize dysfunctional brain activity and connectivity in PTSD under cognitive load with simultaneous symptom provocation, adding to a growing body of evidence supporting the therapeutic neuromodulatory effects of NFB. This preliminary study highlights the benefits of alpha-down NFB training as an adjunctive therapy for PTSD and warrants further investigation into its therapeutic effects on cognitive and emotion control in those with PTSD.
Assuntos
Neurorretroalimentação , Transtornos de Estresse Pós-Traumáticos , Humanos , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Transtornos de Estresse Pós-Traumáticos/terapia , Memória de Curto Prazo , Emoções , Encéfalo , Imageamento por Ressonância Magnética/métodosRESUMO
Collective research has identified a key electroencephalogram signature in patients with post-traumatic stress disorder, consisting of abnormally reduced alpha (8-12â Hz) rhythms. We conducted a 20-session, double-blind, randomized controlled trial of alpha desynchronizing neurofeedback in patients with post-traumatic stress disorder over 20 weeks. Our objective was to provide mechanistic evidence underlying potential clinical improvements by examining changes in aberrant post-traumatic stress disorder brain rhythms (namely, alpha oscillations) as a function of neurofeedback treatment. We randomly assigned participants with a primary diagnosis of post-traumatic stress disorder (n = 38) to either an experimental group (n = 20) or a sham-control group (n = 18). A multichannel electroencephalogram cap was used to record whole-scalp resting-state activity pre- and post-neurofeedback treatment, for both the experimental and sham-control post-traumatic stress disorder groups. We first observed significantly reduced relative alpha source power at baseline in patients with post-traumatic stress disorder as compared to an age/sex-matched group of neurotypical healthy controls (n = 32), primarily within regions of the anterior default mode network. Post-treatment, we found that only post-traumatic stress disorder patients in the experimental neurofeedback group demonstrated significant alpha resynchronization within areas that displayed abnormally low alpha power at baseline. In parallel, we observed significantly decreased post-traumatic stress disorder severity scores in the experimental neurofeedback group only, when comparing baseline to post-treatment (Cohen's d = 0.77) and three-month follow-up scores (Cohen's d = 0.75), with a remission rate of 60.0% at the three-month follow-up. Overall, our results indicate that neurofeedback training can rescue pathologically reduced alpha rhythmicity, a functional biomarker that has repeatedly been linked to symptoms of hyperarousal and cortical disinhibition in post-traumatic stress disorder. This randomized controlled trial provides long-term evidence suggesting that the 'alpha rebound effect' (i.e. homeostatic alpha resynchronization) occurs within key regions of the default mode network previously implicated in post-traumatic stress disorder.
RESUMO
BACKGROUND: Alterations within large-scale brain networks-namely, the default mode (DMN) and salience networks (SN)-are present among individuals with posttraumatic stress disorder (PTSD). Previous real-time functional magnetic resonance imaging (fMRI) and electroencephalography neurofeedback studies suggest that regulating posterior cingulate cortex (PCC; the primary hub of the posterior DMN) activity may reduce PTSD symptoms and recalibrate altered network dynamics. However, PCC connectivity to the DMN and SN during PCC-targeted fMRI neurofeedback remains unexamined and may help to elucidate neurophysiological mechanisms through which these symptom improvements may occur. METHODS: Using a trauma/emotion provocation paradigm, we investigated psychophysiological interactions over a single session of neurofeedback among PTSD (n = 14) and healthy control (n = 15) participants. We compared PCC functional connectivity between regulate (in which participants downregulated PCC activity) and view (in which participants did not exert regulatory control) conditions across the whole-brain as well as in a priori specified regions-of-interest. RESULTS: During regulate as compared to view conditions, only the PTSD group showed significant PCC connectivity with anterior DMN (dmPFC, vmPFC) and SN (posterior insula) regions, whereas both groups displayed PCC connectivity with other posterior DMN areas (precuneus/cuneus). Additionally, as compared with controls, the PTSD group showed significantly greater PCC connectivity with the SN (amygdala) during regulate as compared to view conditions. Moreover, linear regression analyses revealed that during regulate as compared to view conditions, PCC connectivity to DMN and SN regions was positively correlated to psychiatric symptoms across all participants. CONCLUSION: In summary, observations of PCC connectivity to the DMN and SN provide emerging evidence of neural mechanisms underlying PCC-targeted fMRI neurofeedback among individuals with PTSD. This supports the use of PCC-targeted neurofeedback as a means by which to recalibrate PTSD-associated alterations in neural connectivity within the DMN and SN, which together, may help to facilitate improved emotion regulation abilities in PTSD.
Assuntos
Neocórtex , Neurorretroalimentação , Transtornos de Estresse Pós-Traumáticos , Humanos , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Transtornos de Estresse Pós-Traumáticos/terapia , Giro do Cíngulo , Neurorretroalimentação/métodos , Imageamento por Ressonância Magnética , Rede de Modo Padrão/patologia , Encéfalo , Tonsila do Cerebelo , Mapeamento EncefálicoRESUMO
BACKGROUND: Given the highly stressful environment surrounding the SARS-CoV-2 pandemic, healthcare workers (HCW) and public safety personnel (PSP) are at an elevated risk for adverse psychological outcomes, including posttraumatic stress disorder (PTSD) and alcohol/substance use problems. As such, the study aimed to identify associations between PTSD severity, related dissociation and emotion dysregulation symptoms, and alcohol/substance use problems among HCWs and PSP. METHODS: A subset of data (N = 498; HCWs = 299; PSP = 199) was extracted from a larger study examining psychological variables among Canadian HCWs and PSP during the pandemic. Structural equation modelling assessed associations between PTSD symptoms and alcohol/substance use-related problems with dissociation and emotion dysregulation as mediators. RESULTS: Among HCWs, dissociation fully mediated the relation between PTSD and alcohol-related problems (indirect effect ß = .133, p = .03) and emotion dysregulation partially mediated the relation between PTSD and substance-related problems (indirect effect ß = .151, p = .046). In PSP, emotion dysregulation fully mediated the relation between PTSD and alcohol-related problems (indirect effects ß = .184, p = .005). For substance-related problems among PSP, neither emotion dysregulation nor dissociation (ps >.05) had any effects. CONCLUSION: To our knowledge, this is the first study examining associations between PTSD severity and alcohol/substance use-related problems via mediating impacts of emotion dysregulation and dissociation among HCWs and PSP during the SARS-CoV-2 pandemic. These findings highlight dissociation and emotion dysregulation as important therapeutic targets for structured interventions aimed at reducing the burden of PTSD and/or SUD among Canadian HCWs or PSP suffering from the adverse mental health impacts of the SARS-CoV-2 pandemic.
Among healthcare workers, dissociation mediated relation between posttraumatic stress disorder (PTSD) severity and alcohol-related problems and emotion dysregulation mediated relation between PTSD severity and substance-related problems.Among public safety personnel, emotion dysregulation mediated relation between PTSD severity and alcohol-related problems. Neither dissociation nor emotion dysregulation mediated relation between PTSD severity and substance-related problems.Results underscore dissociation and emotion dysregulation as potential key therapeutic targets for intervention for healthcare workers and public safety personnel struggling with PTSD and comorbid alcohol/substance use-related problems.
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COVID-19 , Transtornos Relacionados ao Uso de Substâncias , Humanos , Emoções , SARS-CoV-2 , Pandemias , COVID-19/epidemiologia , Canadá/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/terapia , Pessoal de SaúdeRESUMO
Importance: Adverse life experiences have been proposed to contribute to diverse mental health problems through an association with corticolimbic functioning. Despite compelling evidence from animal models, findings from studies in humans have been mixed; activation likelihood estimation (ALE) meta-analyses have failed to identify a consistent association of adverse events with brain function. Objective: To investigate the association of adversity exposure with altered brain reactivity using multilevel kernel density analyses (MKDA), a meta-analytic approach considered more robust than ALE to small sample sizes and methodological differences between studies. Data Sources: Searches were conducted using PsycInfo, Medline, EMBASE, and Web of Science from inception through May 4, 2022. The following search term combinations were used for each database: trauma, posttraumatic stress disorder (PTSD), abuse, maltreatment, poverty, adversity, or stress; and functional magnetic resonance imaging (fMRI) or neuroimaging; and emotion, emotion regulation, memory, memory processing, inhibitory control, executive functioning, reward, or reward processing. Study Selection: Task-based fMRI studies within 4 domains (emotion processing, memory processing, inhibitory control, and reward processing) that included a measure of adverse life experiences and whole-brain coordinate results reported in Talairach or Montreal Neurological Institute space were included. Conference abstracts, books, reviews, meta-analyses, opinions, animal studies, articles not in English, and studies with fewer than 5 participants were excluded. Data Extraction and Synthesis: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline, 2 independent reviewers assessed abstracts and full-text articles for entry criteria. A third reviewer resolved conflicts and errors in data extraction. Data were pooled using a random-effects model and data analysis occurred from August to November 2022. Main Outcomes and Measures: Peak activation x-axis (left-right), y-axis (posterior-anterior), and z-axis (inferior-superior) coordinates were extracted from all studies and submitted to MKDA meta-analyses. Results: A total of 83 fMRI studies were included in the meta-analysis, yielding a combined sample of 5242 participants and 801 coordinates. Adversity exposure was associated with higher amygdala reactivity (familywise error rate corrected at P < .001; x-axis = 22; y-axis = -4; z-axis = -17) and lower prefrontal cortical reactivity (familywise error rate corrected at P < .001; x-axis = 10; y-axis = 60; z-axis = 10) across a range of task domains. These altered responses were only observed in studies that used adult participants and were clearest among those who had been exposed to severe threat and trauma. Conclusions and Relevance: In this meta-analysis of fMRI studies of adversity exposure and brain function, prior adversity exposure was associated with altered adult brain reactivity to diverse challenges. These results might better identify how adversity diminishes the ability to cope with later stressors and produces enduring susceptibility to mental health problems.
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Acontecimentos que Mudam a Vida , Imageamento por Ressonância Magnética , Adulto , Humanos , Academias e Institutos , Encéfalo/diagnóstico por imagem , NeuroimagemRESUMO
OBJECTIVE: Posttraumatic stress disorder (PTSD) is a debilitating psychiatric illness, experienced by approximately 10% of the population. Heterogeneous presentations that include heightened dissociation, comorbid anxiety and depression, and emotion dysregulation contribute to the severity of PTSD, in turn, creating barriers to recovery. There is an urgent need to use data-driven approaches to better characterize complex psychiatric presentations with the aim of improving treatment outcomes. We sought to determine if machine learning models could predict PTSD-related illness in a real-world treatment-seeking population using self-report clinical data. METHOD: Secondary clinical data from 2017 to 2019 included pretreatment measures such as trauma-related symptoms, other mental health symptoms, functional impairment, and demographic information from adults admitted to an inpatient unit for PTSD in Canada (n = 393). We trained two nonlinear machine learning models (extremely randomized trees) to identify predictors of (a) PTSD symptom severity and (b) functional impairment. We assessed model performance based on predictions in novel subsets of patients. RESULTS: Approximately 43% of the variance in PTSD symptom severity (R²avg = .43, R²median = .44, p = .001) was predicted by symptoms of anxiety, dissociation, depression, negative trauma-related beliefs about others, and emotion dysregulation. In addition, 32% of the variance in functional impairment scores (R²avg = .32, R²median = .33, p = .001) was predicted by anxiety, PTSD symptom severity, cognitive dysfunction, dissociation, and depressive symptoms. CONCLUSIONS: Our results reinforce that dissociation, cooccurring anxiety and depressive symptoms, maladaptive trauma appraisals, cognitive dysfunction, and emotion dysregulation are critical targets for trauma-related interventions. Machine learning models can inform personalized medicine approaches to maximize trauma recovery in real-world inpatient populations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Introduction: Real-time fMRI-based neurofeedback (rt-fMRI-NFB) is a non-invasive technology that enables individuals to self-regulate brain activity linked to neuropsychiatric symptoms, including those associated with post-traumatic stress disorder (PTSD). Selecting the target brain region for neurofeedback-mediated regulation is primarily informed by the neurobiological characteristics of the participant population. There is a strong link between PTSD symptoms and multiple functional disruptions in the brain, including hyperactivity within both the amygdala and posterior cingulate cortex (PCC) during trauma-related processing. As such, previous rt-fMRI-NFB studies have focused on these two target regions when training individuals with PTSD to regulate neural activity. However, the differential effects of neurofeedback target selection on PTSD-related neural activity and clinical outcomes have not previously been investigated. Methods: Here, we compared whole-brain activation and changes in PTSD symptoms between PTSD participants (n = 28) that trained to downregulate activity within either the amygdala (n = 14) or the PCC (n = 14) while viewing personalized trauma words. Results: For the PCC as compared to the amygdala group, we observed decreased neural activity in several regions implicated in PTSD psychopathology - namely, the bilateral cuneus/precuneus/primary visual cortex, the left superior parietal lobule, the left occipital pole, and the right superior temporal gyrus/temporoparietal junction (TPJ) - during target region downregulation using rt-fMRI-NFB. Conversely, for the amygdala as compared to the PCC group, there were no unique (i.e., over and above that of the PCC group) decreases in neural activity. Importantly, amygdala downregulation was not associated with significantly improved PTSD symptoms, whereas PCC downregulation was associated with reduced reliving and distress symptoms over the course of this single training session. In this pilot analysis, we did not detect significant between-group differences in state PTSD symptoms during neurofeedback. As a critical control, the PCC and amygdala groups did not differ in their ability to downregulate activity within their respective target brain regions. This indicates that subsequent whole-brain neural activation results can be attributed to the effects of the neurofeedback target region selection in terms of neurophysiological function, rather than as a result of group differences in regulatory success. Conclusion: In this study, neurofeedback-mediated downregulation of the PCC was differentially associated with reduced state PTSD symptoms and simultaneous decreases in PTSD-associated brain activity during a single training session. This novel analysis may guide researchers in choosing a neurofeedback target region in future rt-fMRI-NFB studies and help to establish the clinical efficacy of specific neurofeedback targets for PTSD. A future multi-session clinical trial of rt-fMRI-NFB that directly compares between PCC and amygdala target regions is warranted.
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Background: Afghan refugees often face hardship and traumatic experiences before, during, and after migration and frequently suffer from mental health burdens. Evidence based psychological treatments for refugees mostly focus on symptoms of posttraumatic stress disorder (PTSD), however, refugees often suffer from a variety of general health problems as well as depression and anxiety. We thus aimed to evaluate the effectiveness of a transdiagnostic psychological intervention. Objective: To investigate the effectiveness of an adapted version of Problem Management Plus (aPM+) delivered by mental health professionals to adult Afghan refugees and asylum seekers. Methods: We randomly allocated 88 Afghan refugees either to aPM+ in addition to treatment as usual (aPM+/TAU) or TAU alone. APM+ comprises of six weekly 90-minute individual sessions including strategies of stress management, problem solving, behavioural activation, strengthening social support and either anger regulation or increasing self-efficacy. The primary outcome was general health (GHQ-28) post intervention. Secondary outcome measures included distress by PMLD, Complex PTSD symptoms, quality of life, self-identified problems, and integration. Results: Attrition was high: 42% of the randomized participants did not participate in the post-treatment assessment. A repeated measures per-protocol (completers only) ANCOVA evidenced a significant group × timepoint interaction for GHQ total scores [F(1, 47) = 14.80, p < .001, partial η2 = 0.24]. Post-hoc analyses showed significantly lower symptoms in the aPM+/TAU arm (n = 26) as compared to the TAU arm (n = 25) for the GHQ total scores (dz = 1.04). Most secondary outcomes significantly improved in the aPM+/TAU arm, but not in the TAU arm. Conclusion: APM+ was effective in reducing general health problems in Afghan refugees and might be considered as a first-line intervention. High drop-out rate limit the interpretations of our results, where future investigations should focus on possibilities to reduce these rates.Trial registration: Uniform Trial Number identifier: U1111-1226-3285. HIGHLIGHTS: Refugees' mental health can be strengthened with a brief psychological intervention that also focuses on skills in the context of post-migration stressors.High drop-out rates are a major challenge for future research and delivery of psychological interventions as part of health care systems to refugees and asylum seekers.
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Refugiados , Transtornos de Estresse Pós-Traumáticos , Adulto , Áustria , Humanos , Intervenção Psicossocial , Qualidade de Vida , Refugiados/psicologia , Transtornos de Estresse Pós-Traumáticos/terapiaRESUMO
Background: While many elaborated treatment protocols focus on post-traumatic stress symptoms, a large number of refugees suffer from a range of mental health problems. Thus, brief and transdiagnostic psychological interventions may be helpful first interventions for help-seeking refugees and asylum seekers in a stepped-care approach. Critically, there is limited research on how transdiagnostic interventions are received in general practice in non-specialized mental healthcare settings in high-income countries, where often only mental health professionals (MHPs) are legally allowed to treat people with mental disorders. MHPs may thus deliver such interventions, but their perspective towards them has not yet been investigated. Objective: We aimed to investigate MHPs' perception of the usability of adapted Problem Management Plus (aPM+), a brief transdiagnostic psychological intervention for refugees, which we adapted to address distress caused by post-migration living difficulties (PMLDs). Method: Employing an e-learning tool, we introduced the aPM+ intervention to 59 MHPs and assessed their perspective towards the intervention. We then used an inductive approach to analyse their perspective towards the intervention with open-ended questions. Results: Altogether, 59 MHPs enrolled in the webinar and 29 provided feedback on the intervention. MHPs had a positive view on the intervention but emphasized the importance of situation-specific adaptations to the structure of the manual. The most favoured specific strategies were 'managing stress/slow-breathing', the 'tree of capabilities', and the 'riding the anger' exercise. The last two were additionally developed to reduce distress caused by PMLDs by either enhancing self-efficacy or reducing anger regulation difficulties. Conclusions: An adaptation to aPM+ regarding more flexibility of the manual may enhance the likelihood of MHPs implementing the intervention in their daily practice. Strategies addressing coping with PMLDs could be particularly helpful.Trial registration: German Clinical Trials Register identifier: DRKS00016538. HIGHLIGHTS: Mental health professionals had a positive view on a brief transdiagnostic psychological intervention for refugees but emphasized the importance of situation-specific adaptations to the structure of the manual.Low -intensity interventions may be useful not only in low- and middle-income countries but also in high-income countries as part of a stepped-care approach, even if distributed by MHPs instead of trained laypersons.
Antecedentes: Mientras que muchos protocolos de tratamiento elaborados se enfocan en los síntomas de estrés postraumático, un gran número de refugiados sufren de un rango de problemas de salud mental. Por lo tanto, las intervenciones psicológicas breves y transdiagnósticas pueden ser primeras intervenciones útiles para refugiados en búsqueda de ayuda y solicitantes de asilo en un enfoque de cuidado escalonado. Críticamente, hay limitada investigación sobre el cómo son recibidas las intervenciones transdiagnósticas en la práctica general en entornos de atención de salud no especializados en países de altos ingresos, donde en general sólo se permite legalmente que profesionales de salud mental (PSM en su sigla en inglés) traten a personas con trastornos mentales. Los PSM pueden por tanto entregar tales intervenciones, pero su perspectiva hacia ellas no ha sido aún investigada.Objetivo: Buscamos investigar la percepción de los PSM de la utilidad de Manejo de Problemas Plus adaptada (aPM+, por su sigla en inglés), una intervención psicológica breve transdiagnóstica para refugiados, que adaptamos para abordar el sufrimiento por dificultades vitales post-migración (PMLD por su sigla en inglés).Método: Utilizando una herramienta de e-learning, presentamos la intervención aPM+ a 59 PSM y evaluamos su perspectiva hacia la intervención. Usamos entonces un abordaje inductivo para analizar la perspectiva hacia la intervención con preguntas abiertas.Resultados: En total, 59 PSM se inscribieron en el webinar y 29 proporcionaron retroalimentación sobre la intervención. Los PSM tuvieron una visión positiva de la intervención pero enfatizaron la importancia de las adaptaciones a la estructura del manual específicas a la situación. Las estrategias específicas más favorecidas fueron 'manejando el estrés/respiración pausada' y el 'árbol de capacidades' y el ejercicio 'montando la ira'. Los dos últimos fueron desarrollados adicionalmente para reducir el sufrimiento causado por PLMD a través de la potenciación de la autoeficacia o la reducción de las dificultades de la regulación de la ira.Conclusiones: Una adaptación a aPM+ en relación a una mayor flexibilidad del manual podría aumentar la probabilidad de que los PSM implementen la intervención en su práctica diaria. Las estrategias que aborden el afrontamiento de PMLD podrían ser particularmente útiles.