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1.
Sci Rep ; 14(1): 9375, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38654100

RESUMO

We propose an integrated methodology for the design and fabrication of 3D micromodels that are suitable for the pore-scale study of transport processes in macroporous materials. The micromodels, that bear the pore-scale characteristics of sandstone, such as porosity, mean pore size, etc, are designed following a stochastic reconstruction algorithm that allows for fine-tuning the porosity and the correlation length of the spatial distribution of the solid material. We then construct a series of 3D micromodels at very fine resolution (i.e. 16 µ m) using a state-of-the-art 3D printing infrastructure, specifically a ProJet MJP3600 3D printer, that utilizes the Material Jetting technology. Within the technical constraints of the 3D printer resolution, the fabricated micromodels represent scaled-up replicas of natural sandstones, that are suitable for the study of the scaling between the permeability, the porosity and the mean pore size. The REV- and pore-scale characteristics of the resulting physical micromodels are recovered using a combination of X-ray micro-CT and microfluidic studies. The experimental results are then compared with single-phase flow simulations at pore-scale and geostatistic models in order to determine the effects of the design parameters on the intrinsic permeability and the spatial correlation of the velocity profile. Our numerical and experimental measurements reveal an excellent match between the properties of the designed and fabricated 3D domains, thus demonstrating the robustness of the proposed methodology for the construction of 3D micromodels with fine-tuned and well-controlled pore-scale characteristics. Furthermore, a pore-scale numerical study over a wider range of 3D digital domain realizations reveals a very good match of the measured permeabilities with the predictions of the Kozeny-Carman formulation based on a single control parameter, k 0 , that is found to have a practically constant value for porosities ϕ ≥ 0.2 . This, in turn, enables us to customize the sample size to meet REV constraints, including enlarging pore morphology while considering the Reynolds number. It is also found that at lower porosities there is a significant increase in the fraction of the non-percolating pores, thus leading to different k 0 , as the porosity approaches a numerically determined critical porosity value, ϕ c , where the domain is no longer percolating.

2.
Environ Sci Technol ; 58(6): 2728-2738, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38232385

RESUMO

Understanding geochemical dissolution in porous materials is crucial, especially in applications such as geological CO2 storage. Accurate estimation of reaction rates enhances predictive modeling in geochemical-flow simulations. Fractured porous media, with distinct transport time scales in fractures and the matrix, raise questions about fracture-matrix interface dissolution rates compared to bulk dissolution rate and the scale-dependency of reaction rate averaging. Our investigation delves into these factors, studying the impact of flow rate and mineralogy on interface dissolution patterns. By injecting carbonated water into carbonate rock samples containing a central channel (mimicking fracture hydrodynamics), our study utilized µCT X-ray imaging at 3.3 µm spatial resolution to estimate the reaction rate and capture the change in pore morphology. Results revealed dissolution rates significantly lower (up to 4 orders of magnitude) than batch experiments. Flow rate notably influenced fracture profiles, causing uneven enlargement at low rates and uniform widening at higher ones. Ankerite presence led to a dissolution-altered layer on the fracture surface, showing high permeability and porosity without greatly affecting the dissolution rate, unlike clay-rich carbonates. This research sheds light on controlling factors influencing dissolution in subsurface environments, critical for accurate modeling in diverse applications.


Assuntos
Dióxido de Carbono , Carbonatos , Microtomografia por Raio-X
3.
Rev Sci Instrum ; 94(8)2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38065175

RESUMO

An existing open and modular designed micro X-Ray Computed Tomography (µXRCT) system is extended by a test rig in order to combine mechanical and hydro-mechanical experiments with µXRCT characterization. The aim of the system is to cover the complete resolution range of the underlying µXRCT system in combination with a broad load capacity range. A characteristic feature of the developed setup is that it consists mainly of standard components. This makes the shown test rig potentially interesting for other researchers considering extending an existing µXRCT system with an apparatus for mechanical and hydro-mechanical in situ testing. For the load frame, an uniaxial 10 kN universal testing machine with a digital control system was employed, which was extended by two aligned rotational stages. The uniaxial load capacity is ±3.1 kN and can be combined with torque moments of up to ±15 N m both limited by the used rotational stages. The setup is designed in such a way that different x-ray transparent cells (flow cells, oedometer cells, triaxial cells, etc.) can be integrated to generate three-dimensional stress/strain states as required for porous media research. Three applications demonstrate the possible versatile use of the system. As part of these examples, we show how corresponding x-ray transparent cells are designed and implemented. Finally, we discuss the presented approach's technical advantages and disadvantages and suggest improvements.

4.
Hum Brain Mapp ; 44(3): 1278-1282, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36399510

RESUMO

Continuous real-time functional magnetic resonance imaging (fMRI) neurofeedback is gaining increasing scientific attention in clinical neuroscience and may benefit from the short repetition times of modern multiband echoplanar imaging sequences. However, minimizing feedback delay can result in technical challenges. Here, we report a technical problem we experienced during continuous fMRI neurofeedback with multiband echoplanar imaging and short repetition times. We identify the possible origins of this problem, describe our current interim solution and provide openly available workflows and code to other researchers in case they wish to use a similar approach.


Assuntos
Imagem Ecoplanar , Neurorretroalimentação , Humanos , Imagem Ecoplanar/métodos , Neurorretroalimentação/métodos , Imageamento por Ressonância Magnética/métodos , Atenção , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem
5.
Brain Behav ; 12(1): e2442, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34878219

RESUMO

INTRODUCTION: Arterial spin labeling (ASL) is a functional neuroimaging technique that has been frequently used to investigate acute pain states. A major advantage of ASL as opposed to blood-oxygen-level-dependent functional neuroimaging is its applicability for low-frequency designs. As such, ASL represents an interesting option for studies in which repeating an experimental event would reduce its ecological validity. Whereas most ASL pain studies so far have used thermal stimuli, to our knowledge, no ASL study so far has investigated pain responses to sharp mechanical pain. METHODS: As a proof of concept, we investigated whether ASL has the sensitivity to detect brain activation within core areas of the nociceptive network in healthy controls following a single stimulation block based on 96 s of mechanical painful stimulation using a blunt blade. RESULTS: We found significant increases in perfusion across many regions of the nociceptive network such as primary and secondary somatosensory cortices, premotor cortex, posterior insula, inferior parietal cortex, parietal operculum, temporal gyrus, temporo-occipital lobe, putamen, and the cerebellum. Contrary to our hypothesis, we did not find any significant increase within ACC, thalamus, or PFC. Moreover, we were able to detect a significant positive correlation between pain intensity ratings and pain-induced perfusion increase in the posterior insula. CONCLUSION: We demonstrate that ASL is suited to investigate acute pain in a single event paradigm, although to detect activation within some regions of the nociceptive network, the sensitivity of our paradigm seemed to be limited. Regarding the posterior insula, our paradigm was sensitive enough to detect a correlation between pain intensity ratings and pain-induced perfusion increase. Previous experimental pain studies have proposed that intensity coding in this region may be restricted to thermal stimulation. Our result demonstrates that the posterior insula encodes intensity information for mechanical stimuli as well.


Assuntos
Circulação Cerebrovascular , Dor , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Humanos , Imageamento por Ressonância Magnética/métodos , Dor/diagnóstico por imagem , Lobo Parietal/fisiologia , Marcadores de Spin
6.
Sci Adv ; 7(52): eabj0960, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-34936457

RESUMO

Experimental and field studies reported a significant discrepancy between the cleanup and contamination time scales, while its cause is not yet addressed. Using high-resolution fast synchrotron x-ray computed tomography, we characterized the solute transport in a fully saturated sand packing for both contamination and cleanup processes at similar hydrodynamic conditions. The discrepancy in the time scales has been demonstrated by the nonuniqueness of hydrodynamic dispersion coefficient versus injection rate (Péclet number). Observations show that in the mixed advection-diffusion regime, the hydrodynamic dispersion coefficient of cleanup is significantly larger than that of the contamination process. This nonuniqueness has been attributed to the concentration-dependent diffusion coefficient during the cocurrent and countercurrent advection and diffusion, present in contamination and cleanup processes. The new findings enhance our fundamental understanding of transport processes and improve our capability to estimate the transport time scales of chemicals or pollution in geological and engineering systems.

7.
Rev Sci Instrum ; 91(11): 113102, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33261434

RESUMO

In this paper, a modular and open micro X-ray Computed Tomography (µXRCT) system is presented, which was set up during the last years at the Institute of Applied Mechanics (CE) of the University of Stuttgart and earlier at the Institute of Computational Engineering of Ruhr-University Bochum. The system is characterized by its intrinsic flexibility resulting from the modular and open design on each level and the opportunity to implement advanced experimental in situ setups. On the one hand, the presented work is intended to support researchers interested in setting up an experimental XRCT system for the microstructural characterization of materials. On the other hand, it aims to support scientists confronted with the decision to set up a system on their own or to buy a commercial scanner. In addition to the presentation of the various hardware components and the applied modular software concept, the technical opportunities of the open and modular hard- and software design are demonstrated by implementing a simple and reliable method for the compensation of bad detector pixels to enhance the raw data quality of the projections. A detailed investigation of the performance of the presented system with regard to the achievable spatial resolution is presented. XRCT datasets of three different applications are finally shown and discussed, demonstrating the wide scope of options of the presented system.


Assuntos
Fenômenos Mecânicos , Microtomografia por Raio-X/instrumentação , Desenho de Equipamento , Imagens de Fantasmas , Software
8.
Neuroimage Clin ; 24: 102032, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31795041

RESUMO

Real-time functional magnetic resonance imaging (fMRI) neurofeedback training of amygdala hemodynamic activity directly targets a neurobiological mechanism, which contributes to emotion regulation problems in borderline personality disorder (BPD). However, it remains unknown which outcome measures can assess changes in emotion regulation and affective instability, associated with amygdala downregulation in a clinical trial. The current study directly addresses this question. Twenty-four female patients with a DSM-IV BPD diagnosis underwent four runs of amygdala neurofeedback. Before and after the training, as well as at a six-weeks follow-up assessment, participants completed measures of emotion dysregulation and affective instability at diverse levels of analysis (verbal report, clinical interview, ecological momentary assessment, emotion-modulated startle, heart rate variability, and fMRI). Participants were able to downregulate their amygdala blood oxygen-dependent (BOLD) response with neurofeedback. There was a decrease of BPD symptoms as assessed with the Zanarini rating scale for BPD (ZAN-BPD) and a decrease in emotion-modulated startle to negative pictures after training. Further explorative analyses suggest that patients indicated less affective instability, as seen by lower hour-to-hour variability in negative affect and inner tension in daily life. If replicated by an independent study, our results imply changes in emotion regulation and affective instability for several systems levels, including behavior and verbal report. Conclusions are limited due to the lack of a control group. A randomized controlled trial (RCT) will be needed to confirm effectiveness of the training.


Assuntos
Transtorno da Personalidade Borderline/diagnóstico por imagem , Transtorno da Personalidade Borderline/psicologia , Emoções , Neurorretroalimentação/métodos , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Regulação Emocional , Feminino , Humanos , Imageamento por Ressonância Magnética , Testes Neuropsicológicos , Estimulação Luminosa , Escalas de Graduação Psiquiátrica , Reflexo de Sobressalto , Autoavaliação (Psicologia)
9.
Behav Brain Res ; 369: 111938, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31071348

RESUMO

Receiving feedback from neural activity, dubbed neurofeedback, can reinforce brain self-regulation. In a real-time functional magnetic resonance imaging (fMRI) experiment, healthy participants received amygdala neurofeedback via a visual brain-computer interface. The brain response to signals of reward and failure was modeled. In contrast to previous analyses, we take into account feedback that immediately preceded these signals. That means we tested whether responses were modulated while participants observed sequent reward and failure signals. The orbitofrontal cortex (OFC) showed a negative Blood Oxygenation Level Dependent (BOLD) response to failure signals, when they were preceded by more failure signals. When failure signals were preceded by reward, in contrast, the response was less pronounced. The results suggest weighted processing of neurofeedback value in the OFC. Learning to self-regulate the brain with neurofeedback may involve similar neural networks as the learning of goal-directed action.


Assuntos
Neurorretroalimentação/métodos , Córtex Pré-Frontal/fisiologia , Adulto , Tonsila do Cerebelo/fisiologia , Encéfalo/fisiologia , Mapeamento Encefálico/métodos , Interfaces Cérebro-Computador , Feminino , Voluntários Saudáveis , Humanos , Aprendizagem/fisiologia , Imageamento por Ressonância Magnética/métodos , Reforço Psicológico , Recompensa , Adulto Jovem
10.
Netw Neurosci ; 2(4): 464-480, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30320294

RESUMO

Graph theoretical functional magnetic resonance imaging (fMRI) studies have demonstrated that brain networks reorganize significantly during motor skill acquisition, yet the associations between motor learning ability, brain network features, and the underlying biological mechanisms remain unclear. In the current study, we applied a visually guided sequential pinch force learning task and graph theoretical analyses to investigate the associations between short-term motor learning ability and resting-state brain network metrics in 60 healthy subjects. We further probed the test-retest reliability (n = 26) and potential effects of the N-methyl-d-aspartate (NMDA) antagonist ketamine (n = 19) in independent healthy volunteers. Our results show that the improvement of motor performance after short-term training was positively correlated with small-worldness (p = 0.032) and global efficiency (p = 0.025), whereas negatively correlated with characteristic path length (p = 0.014) and transitivity (p = 0.025). In addition, using network-based statistics (NBS), we identified a learning ability-associated (p = 0.037) and ketamine-susceptible (p = 0.027) cerebellar-cortical network with fair to good reliability (intraclass correlation coefficient [ICC] > 0.7) and higher functional connectivity in better learners. Our results provide new evidence for the association of intrinsic brain network features with motor learning and suggest a role of NMDA-related glutamatergic processes in learning-associated subnetworks.

11.
Hum Brain Mapp ; 39(7): 3018-3031, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29602255

RESUMO

Brain-computer interfaces provide conscious access to neural activity by means of brain-derived feedback ("neurofeedback"). An individual's abilities to monitor and control feedback are two necessary processes for effective neurofeedback therapy, yet their underlying functional neuroanatomy is still being debated. In this study, healthy subjects received visual feedback from their amygdala response to negative pictures. Activation and functional connectivity were analyzed to disentangle the role of brain regions in different processes. Feedback monitoring was mapped to the thalamus, ventromedial prefrontal cortex (vmPFC), ventral striatum (VS), and rostral PFC. The VS responded to feedback corresponding to instructions while rPFC activity differentiated between conditions and predicted amygdala regulation. Control involved the lateral PFC, anterior cingulate, and insula. Monitoring and control activity overlapped in the VS and thalamus. Extending current neural models of neurofeedback, this study introduces monitoring and control of feedback as anatomically dissociated processes, and suggests their important role in voluntary neuromodulation.


Assuntos
Tonsila do Cerebelo/fisiologia , Emoções/fisiologia , Neuroimagem Funcional/métodos , Neurorretroalimentação/métodos , Reconhecimento Visual de Modelos/fisiologia , Córtex Pré-Frontal/fisiologia , Autocontrole , Tálamo/fisiologia , Estriado Ventral/fisiologia , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Interfaces Cérebro-Computador , Feminino , Humanos , Imageamento por Ressonância Magnética , Córtex Pré-Frontal/diagnóstico por imagem , Tálamo/diagnóstico por imagem , Estriado Ventral/diagnóstico por imagem , Adulto Jovem
12.
Neuroscience ; 378: 89-99, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-27659116

RESUMO

Neurofeedback training (NF) is a promising non-pharmacological treatment for ADHD that has been associated with improvement of attention-deficit/hyperactivity disorder (ADHD)-related symptoms as well as changes in electrophysiological measures. However, the functional localization of neural changes following NF compared to an active control condition, and of successful learning during training (considered to be the critical mechanism for improvement), remains largely unstudied. Children with ADHD (N=16, mean age: 11.81, SD: 1.47) were randomly assigned to either slow cortical potential (SCP, n=8) based NF or biofeedback control training (electromyogram feedback, n=8) and performed a combined Flanker/NoGo task pre- and post-training. Effects of NF, compared to the active control, and of learning in transfer trials (approximating successful transfer to everyday life) were examined with respect to clinical outcome and functional magnetic resonance imaging (fMRI) changes during inhibitory control. After 20 sessions of training, children in the NF group presented reduced ADHD symptoms and increased activation in areas associated with inhibitory control compared to baseline. Subjects who were successful learners (n=9) also showed increased activation in an extensive inhibitory network irrespective of the type of training. Activation increased in an extensive inhibitory network following NF training, and following successful learning through NF and control biofeedback. Although this study was only powered to detect large effects and clearly requires replication in larger samples, the results suggest a crucial role for learning effects in biofeedback trainings.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Transtorno do Deficit de Atenção com Hiperatividade/reabilitação , Encéfalo/fisiopatologia , Inibição Psicológica , Aprendizagem , Neurorretroalimentação , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Criança , Eletroencefalografia , Eletromiografia , Feminino , Humanos , Aprendizagem/fisiologia , Imageamento por Ressonância Magnética , Masculino , Neurorretroalimentação/métodos , Neurorretroalimentação/fisiologia , Autocontrole , Resultado do Tratamento
14.
JAMA Psychiatry ; 74(9): 949-957, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28768322

RESUMO

Importance: Although borderline personality disorder (BPD)-one of the most common, burdensome, and costly psychiatric conditions-is characterized by repeated interpersonal conflict and instable relationships, the neurobiological mechanism of social interactive deficits remains poorly understood. Objective: To apply recent advancements in the investigation of 2-person human social interaction to investigate interaction difficulties among people with BPD. Design, Setting, and Participants: Cross-brain information flow in BPD was examined from May 25, 2012, to December 4, 2015, in pairs of participants studied in 2 linked functional magnetic resonance imaging scanners in a university setting. Participants performed a joint attention task. Each pair included a healthy control individual (HC) and either a patient currently fulfilling DSM-IV criteria for BPD (cBPD) (n = 23), a patient in remission for 2 years or more (rBPD) (n = 17), or a second HC (n = 20). Groups were matched for age and educational level. Main Outcomes and Measures: A measure of cross-brain neural coupling was computed following previously published work to indicate synchronized flow between right temporoparietal junction networks (previously shown to host neural coupling abilities in health). This measure is derived from an independent component analysis contrasting the time courses of components between pairs of truly interacting participants compared with bootstrapped control pairs. Results: In the sample including 23 women with cBPD (mean [SD] age, 26.8 [5.7] years), 17 women with rBPD (mean [SD] age, 28.5 [4.3] years), and 80 HCs (mean [SD] age, 24.0 [3.4] years]) investigated as dyads, neural coupling was found to be associated with disorder state (η2 = 0.17; P = .007): while HC-HC pairs showed synchronized neural responses, cBPD-HC pairs exhibited significantly lower neural coupling just above permutation-based data levels (η2 = 0.16; P = .009). No difference was found between neural coupling in rBPD-HC and HC-HC pairs. The neural coupling in patients was significantly associated with childhood adversity (T = 2.3; P = .03). Conclusions and Relevance: This study provides a neural correlate for a core diagnostic and clinical feature of BPD. Results indicate that hyperscanning may deliver state-associated biomarkers for clinical social neuroscience. In addition, at least some neural deficits of BPD may be more reversible than is currently assumed for personality disorders.


Assuntos
Transtorno da Personalidade Borderline/fisiopatologia , Córtex Cerebral/fisiopatologia , Relações Interpessoais , Desempenho Psicomotor/fisiologia , Adulto , Mapeamento Encefálico , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética , Indução de Remissão , Adulto Jovem
15.
Neuropsychopharmacology ; 42(12): 2456-2465, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27869141

RESUMO

Autism spectrum disorders (ASDs) and obsessive compulsive disorder (OCD) are often comorbid with the overlap based on compulsive behaviors. Although previous studies suggest glutamatergic deficits in fronto-striatal brain areas in both disorders, this is the first study to directly compare the glutamate concentrations across the two disorders with those in healthy control participants using both categorical and dimensional approaches. In the current multi-center study (four centers), we used proton magnetic resonance spectroscopy in 51 children with ASD, 29 with OCD, and 53 healthy controls (aged 8-13 years) to investigate glutamate (Glu) concentrations in two regions of the fronto-striatal circuit: midline anterior cingulate cortex (ACC) and left dorsal striatum. Spectra were processed with Linear Combination Model. Group comparisons were performed with one-way analyses of variance including sex, medication use, and scanner site as covariates. In addition, a dimensional analysis was performed, linking glutamate with a continuous measure of compulsivity across disorders. There was a main group effect for ACC glutamate (p=0.019). Contrast analyses showed increased glutamate both in children with ASD and OCD compared with controls (p=0.007), but no differences between the two disorders (p=0.770). Dimensional analyses revealed a positive correlation between compulsive behavior (measured with the Repetitive Behavior Scale) and ACC glutamate (rho=0.24, p=0.03). These findings were robust across sites. No differences were found in the striatum. The current findings confirm overlap between ASD and OCD in terms of glutamate involvement. Glutamate concentration in ACC seems to be associated with the severity of compulsive behavior.


Assuntos
Transtorno do Espectro Autista/metabolismo , Corpo Estriado/metabolismo , Lobo Frontal/metabolismo , Ácido Glutâmico/metabolismo , Transtorno Obsessivo-Compulsivo/metabolismo , Adolescente , Transtorno do Espectro Autista/diagnóstico , Criança , Feminino , Humanos , Espectroscopia de Ressonância Magnética/métodos , Masculino , Transtorno Obsessivo-Compulsivo/diagnóstico
16.
Psychophysiology ; 53(10): 1460-71, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27412783

RESUMO

Exaggerated conditioned fear responses and impaired extinction along with amygdala overactivation have been observed in posttraumatic stress disorder (PTSD). These fear responses might be triggered by cues related to the trauma through higher-order conditioning, where reminders of the trauma may serve as unconditioned stimuli (US) and could maintain the fear response. We compared arousal, valence, and US expectancy ratings and BOLD brain responses using fMRI in 14 traumatized persons with PTSD and 14 without PTSD (NPTSD) and 13 matched healthy controls (HC) in a differential aversive conditioning paradigm. The US were trauma-specific pictures for the PTSD and NPTSD group and equally aversive and arousing for the HC; the conditioned stimuli (CS) were graphic displays. During conditioning, the PTSD patients compared to the NPTSD and HC indicated higher arousal to the conditioned stimulus that was paired with the trauma picture (CS+) compared to the unpaired (CS-), increased dissociation during acquisition and extinction, and failure to extinguish the CS/US-association compared to NPTSD. During early and late acquisition, the PTSD patients showed a significantly lower amygdala activation to CS+ versus CS- and a negative interaction between activation in the amygdala and dorsolateral prefrontal cortex (PFC), while NPTSD and HC displayed a negative interaction between amygdala and medial PFC. These findings suggest maladaptive anticipatory coping with trauma-related stimuli in patients with PTSD, indicated by enhanced conditioning, with related abnormal amygdala reactivity and connectivity, and delayed extinction.


Assuntos
Tonsila do Cerebelo/fisiopatologia , Medo/fisiologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Adulto , Afeto , Nível de Alerta , Encéfalo/fisiopatologia , Mapeamento Encefálico , Condicionamento Clássico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa
17.
Soc Cogn Affect Neurosci ; 11(6): 952-60, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26833918

RESUMO

With the use of real-time functional magnetic resonance imaging neurofeedback (NF), amygdala activitiy can be visualized in real time. In this study, continuous amygdala NF was provided to patients with borderline personality disorder (BPD) with the instruction to down-regulate. During four sessions of NF training, patients viewed aversive pictures and received feedback from a thermometer display, which showed the amygdala blood oxygenation level-dependent signal. Conditions of regulation and viewing without regulation were presented. Each session started with a resting-state scan and was followed by a transfer run without NF. Amygdala regulation, task-related and resting-state functional brain connectivity were analyzed. Self-ratings of dissociation and difficulty in emotion regulation were collected. BPD patients down-regulated right amygdala activation but there were no improvements over time. Task-related amygdala-ventromedial prefrontal cortex connectivity was altered across the four sessions, with an increased connectivity when regulating vs viewing pictures. Resting-state amygdala-lateral prefrontal cortex connectivity was altered and dissociation, as well as scores for 'lack of emotional awareness', decreased with training. Results demonstrated that amygdala NF may improve healthy brain connectivity, as well as emotion regulation. A randomized-controlled trial is needed to investigate whether amygdala NF is instrumental for improving neural regulation and emotion regulation in BPD patients.


Assuntos
Tonsila do Cerebelo/fisiopatologia , Transtorno da Personalidade Borderline/fisiopatologia , Interfaces Cérebro-Computador , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiopatologia , Neurorretroalimentação/fisiologia , Córtex Pré-Frontal/fisiopatologia , Adulto , Transtorno da Personalidade Borderline/reabilitação , Humanos , Neurorretroalimentação/métodos
18.
Neural Plast ; 2016: 8240894, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26819776

RESUMO

This study investigated the impact of "life kinetik" training on brain plasticity in terms of an increased functional connectivity during resting-state functional magnetic resonance imaging (rs-fMRI). The training is an integrated multimodal training that combines motor and cognitive aspects and challenges the brain by introducing new and unfamiliar coordinative tasks. Twenty-one subjects completed at least 11 one-hour-per-week "life kinetik" training sessions in 13 weeks as well as before and after rs-fMRI scans. Additionally, 11 control subjects with 2 rs-fMRI scans were included. The CONN toolbox was used to conduct several seed-to-voxel analyses. We searched for functional connectivity increases between brain regions expected to be involved in the exercises. Connections to brain regions representing parts of the default mode network, such as medial frontal cortex and posterior cingulate cortex, did not change. Significant connectivity alterations occurred between the visual cortex and parts of the superior parietal area (BA7). Premotor area and cingulate gyrus were also affected. We can conclude that the constant challenge of unfamiliar combinations of coordination tasks, combined with visual perception and working memory demands, seems to induce brain plasticity expressed in enhanced connectivity strength of brain regions due to coactivation.


Assuntos
Encéfalo/fisiologia , Cognição/fisiologia , Conectoma , Exercício Físico/fisiologia , Rede Nervosa/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade
19.
Eur Addict Res ; 22(2): 80-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26343988

RESUMO

We explored brain volume recovery in terms of cortical thickness (CTh; gyral, sulcal pattern) and surface area (SA), as well as subcortical volume recovery in the first 2 weeks of abstinence in 49 alcohol-dependent patients (ADPs). A widespread reduction of CTh in ADPs at day 1 of abstinence compared to healthy controls, with more pronounced differences in sulci relative to gyri was found. After 2 weeks of abstinence, partial recovery to varying degrees of CTh loss in ADPs was observed for several regions. The longitudinal CTh changes were greater in sulci than in gyri of affected regions. No longitudinal change in SAs and subcortical volumes was found. Alterations of CTh contribute to brain volume loss in alcoholism and recovery during early abstinence. Sulci seem to be more vulnerable to excessive alcohol consumption and to drive abstinence-induced volume recovery. During the initial 2 weeks of abstinence no subcortical volume regain was observed. Either the time span was too short or the lower subcortical volume could represent a predisposing trait marker.


Assuntos
Abstinência de Álcool , Alcoolismo/patologia , Encéfalo/patologia , Córtex Cerebral/patologia , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Tamanho do Órgão , Fatores de Tempo
20.
Neuroimage ; 125: 182-188, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26481674

RESUMO

Down-regulation of the amygdala with real-time fMRI neurofeedback (rtfMRI NF) potentially allows targeting brain circuits of emotion processing and may involve prefrontal-limbic networks underlying effective emotion regulation. Little research has been dedicated to the effect of rtfMRI NF on the functional connectivity of the amygdala and connectivity patterns in amygdala down-regulation with neurofeedback have not been addressed yet. Using psychophysiological interaction analysis of fMRI data, we present evidence that voluntary amygdala down-regulation by rtfMRI NF while viewing aversive pictures was associated with increased connectivity of the right amygdala with the ventromedial prefrontal cortex (vmPFC) in healthy subjects (N=16). In contrast, a control group (N=16) receiving sham feedback did not alter amygdala connectivity (Group×Condition t-contrast: p<.05 at cluster-level). Task-dependent increases in amygdala-vmPFC connectivity were predicted by picture arousal (ß=.59, p<.05). A dynamic causal modeling analysis with Bayesian model selection aimed at further characterizing the underlying causal structure and favored a bottom-up model assuming predominant information flow from the amygdala to the vmPFC (xp=.90). The results were complemented by the observation of task-dependent alterations in functional connectivity of the vmPFC with the visual cortex and the ventrolateral PFC in the experimental group (Condition t-contrast: p<.05 at cluster-level). Taken together, the results underscore the potential of amygdala fMRI neurofeedback to influence functional connectivity in key networks of emotion processing and regulation. This may be beneficial for patients suffering from severe emotion dysregulation by improving neural self-regulation.


Assuntos
Tonsila do Cerebelo/fisiologia , Emoções/fisiologia , Vias Neurais/fisiologia , Neurorretroalimentação/métodos , Adulto , Mapeamento Encefálico/métodos , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Lobo Límbico/fisiologia , Imageamento por Ressonância Magnética , Córtex Pré-Frontal/fisiologia , Adulto Jovem
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